G6 Series
80+ Mid Efficiency Uptlow Horizontal/ Downflow Models
Service Manual
TABLE OF CONTENTS
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. Circulating Air SUDPIY veeece.heecnccseceeitioncceeeeeeiecd east 7 FAS ECU oes canseietreneerasilesedequogeniste ban dacoananttneseausatecenesaaneeds 7 PMIOW DAN esicrs cee viata a tocausaucbesnntaieusteteuhemebianers 8
. Venting and Combustion Air Requirements ............... 9 Installation In An Unconfined Space .............::::000ccee 9 Installation in a Confined Space .............ccccceseeeeeeee ees 9 Air From INSid@ ............cccceececeeceeeeeceeeececeeeeeseeeeseeeeees 10 Outdoor Air Using Vertical Ducts ................ccceeeeees 10 Air Directly Through An Exterior Wall .................00. 11 Outdoor Air Using Horizontal Ducts ...................0066 11 Category | Common Venting ..............ccccceeeceeeeeeees 12 Category Ill Horizontal Venting ................cccceeeeeeees 13
POM GORA ses vcacscecovsnntanencnsaunshettarcaciantenivecsaenventins 13 FOr GOAK 46 iccce tie taenahiaeaeeemas eee 14 Vent Kit Bleed Tube Chart ..............ccccccccseesseeeeeeeeees 40 Through-The-Wall Power Venting ...............c::sccceeees 15 Location of Outdoor Termination ................:ccceeeeeeees 16 Horizontal Installation ..............cccccccesseeeeeseeeeeeeees 16 Flexible Vent SYSteMs ............cccccceseecceceeseeeeeeeeaeeees 17 ME AK GOGH mre eees cele os ro ddeee teste ee cal 17 EICCINIGAl VVININGatrsiaricsntSivsteeidciuncoristetia tee alaeaees 17
. System Operation Information ..............cccceeeceeeeeeeees 17 SEQUENCE Of OPErAatiON ..........ccccseeceeeessseeeeesseeeeeeeeees 17 FICAUNG MOUS esccccn:vedenconncedvacdadauetdexssenteeeecansaeaecstes 17 COOUNG MOE; iis sictecstes cian euetideoncdedveuat coamssdaucceeners 18 FAN IMO GG era. cn ciate tvttestlice ei state e ouheeteaectouhatihete sas 18 Furnace Fails To Operate ............ccccscccecsseeeeeseeeeeeees 18 WAAIATNAG 224 ccacesesed 2 seecanachostscancseteanlosseenasteaesaan, bececes 18
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COMPONENT Parts ..........cceeeeccescssseeeeeeeeceseeeeeeeeesseaees 19 LING V ON aOe: veiwimsisivneliat aactoseviee aaa 19 S10] 6) 6) \YAAVA0) | ¢- (0 =e 20 Trouble Shooting SEQUENCE ............:ccceeeeeeeeeeeeeeeeees 21 UTEC Control Board Sequence .............ccccesseeeeeeeees 22 Wiring Diagram - GGRA Upflow .............cccecseeeeeeeeees 23 Wiring Diagram - GBRK Downflow...............::00cceeeeee 24 Polarity anc: Ground aces ectsutveessetitacrenitaatengesttelicsee 25 Blower Door SWItch ..............ccccceecceseeeeeceeeeeseeeseaees 25 ANISTON Cl <ce cre esesectsae seine tases o.craneseaeeenas 25 LOW Voltage WIIG ...........cccseececseececeeseeeeeeesseeeeeseuees 26 CONMMWOIIBOANG: stiatiiaxteoniiuis ees diceuntasldianieraceacs: 26,27 High Limit COntrols ...........cccccsseeeceeeeeeeeeeeeeeseeeeeeeeeees 28 Mair-Arr Limit: COMO seicsesctaseeasinavavseweinaccserteteess 29 Vent Limit Control .............cccccccccecsssceeeeeeeeeeeeeeeeeeeees 29 Roll Our imit: GOntOl :izisehids cereus siaastniearaseiteions 30 Draft Inducer MOtOr.............cccccccseceeeeeseeeeeeeeeeeeeeeeeees 30 PRESSULE SWITCH sete sceciasr cutee aan 30 Hot Surface IQnitOr ............cccccceeeccceeeeeseeeeeseaeeeeeeeeens 33 (Gas VIVE iis csessineeetaenldiataeseab ea eaiateiclonenaae: 34 FAME SCNSOM: asi aves cacsavappaadacds beret dancubsdvaasenanuunediune 35 Heat Exchanger and Its Components ................:006 35 Blower Performance: .............cscccsseeceeeeseseeeeeeseeeeeeees 36 Flue Gas Temperature ............ccccccsseeeeceeeeseeeeeseaaeees 36 Gas Conversion and High Altitude ...................cc00 37 High Altitude Derate .............ccccsseeceecsseeeesseseeeseaeeess 37 COME NSIOMN: sascitectes iuvscthesoiee teeny ua canbeannt coasndeeetinaroaaes 37 Verifying and Adjusting Firing Rate ................ccccee 37 PICCOSSONES chess es adttunrnsnceatetden ts Aadsee Gh naesnggae tyes 39 AUC INI -sesiaeetta su entoredic nat tere stesctranstasdsdieese: 39 Natural Gas to Propane Conversion Kits ............... 39 Electronic Air ClOAner ............ccccsecceceeeeeeeeceseeseessaeees 39
G6RA, G6RK Service Manual 1
INTRODUCTION
This service manual is designed to be used in conjunction with the installation manual provided with each furnace.
This furnace represents the very latest in mid efficiency gas furnace technology. Consequently, certain controls within the furnace consist of highly sophisticated electronic components which are not user serviceable. Therefore, it is essential that only competent, qualified service personnel attempt to install, service, or maintain this product.
This service manual was written to assist the professional HVAC service technician to quickly and accurately diagnose and repair any malfunctions of this product.
This service manual covers both upflow/horizontal models and downflow models installed as Category | and Category Ill applications. The overall operation of all these models is basically the same with the exception of certain controls that are unique to a particular model.
This manual, therefore, will deal with all subjects in a general nature (I.E. all text will pertain to all models) unless that subject is unique to a particular model or family, in which case it will be so indicated.
It will be necessary then for you to accurately identify the unit you are servicing, So you may be certain of the approved diagnosis and repair. (See Unit Identification on Page 4.)
This manual was prepared by the senior Technical Service and Communication Departments.
WG ne
The information contained in this manual is intended for use by a qualified service technician who is familiar with the safety procedures required in installation and repair and who is equipped with the proper tools and testing instruments.
Installations and repairs made by unqualified persons can result in hazards subjecting the unqualified person making such repairs to the risk of injury or electrical shock which can be serious or even fatal not only to them, but also to persons being served by the equipment.
If you install or perform service on equipment, you must assume responsibility for any bodily injury or property damage which may result to you or others. We will not be responsible for any injury or property damage arising from improper installation, service, and/or service procedures.
2 G6RA, G6RK Service Manual
FURNACE SPECIFICATIONS - Upflow G6RA Models
| Unit Shown in Upflow Position aie FLUE Rotate 90 Clockwise or Counter Clockwise
OUTLET gi for Horizontal Application
| ~ 19 3/4 iy 3/4 —>| |<——_ | —>||«—3/4 —_A a Ge eee eee
11/2 X 31/2 Cut-out for ; Gas Connection
11/2 X 31/2 Cut-out for (\« Gas Connection
oCo
7g Cut-out for Electric 7/g Cut-out for Connection Electric Connection
25 5/3 ————_——_> | Return
Air Opening (Side)
« D > <« 11/4 11/4 |~q—_____- 23 ——+| Return Air Opening
(Bottom) $gat_— 275/, ——————_
Figure 1.G6RA Unit Dimensions
FURNACE DIMENSIONS AND SHIPPING WEIGHTS
G6RA096(")-20 20 G6RA120(")-16| 120,000 | 1939/4 | 181/4 | 39/4 __ 17. 1/4 G6RA120(")-20 20 G6RA144(")-20 20
Table 1A. G6RA Furnace Dimensions and Shipping Weights
Furnace Dimensions Shipping
Input A B C Flue Outlet} Weight D
Model (Btuh) (in.) (in.) (in.) (in.) (Ibs) (IN.) G6RA045(*)-08 G6RA06O(*)-12 G6RAO72(*)-12 G6RA072(*)-16 G6RA096(*)-12 G6RA096(*)-16 | | 4 | tes | 20
83
G6RA, G6RK Service Manual 3
FURNACE SPECIFICATIONS - Downflow G6RK Models
~<a = 4" Dia. Vent | " "Dia. Ven ae 3/4 | | x 3/4" | |< |B ——>||=a-3/4" ee oo es
——a_§|_*¥_?24 1/2" Cut-out for Electric
Both sides
oo 25"
Cut-out for Gas Connection
1-1/2 x 3-1/2 (both sides) —«— Cut - out for
Gas Connection
3/4" | |<g—__19 3/4 ——a—— B-—_ (Bottom Opening) (Bottom Opening)
—<4—____27 7/8"—______»
Figure 1A. GGRK Unit Dimensions
FURNACE DIMENSIONS AND SHIPPING WEIGHTS
Furnace Dimensions Shipping
(Btuh) inches (Ibs)
120,000
Table 1B. G6RK Furnace Dimensions and Shipping Weights
4 G6RA, G6RK Service Manual
MODEL IDENTIFICATION CODE G 6 R A — 040 C Nominal CFM Airflow
@ 0.5" WC Gas | | 08 = 800 16 = 1600 12 = 1200 20 = 2000 Design Series
C =U.S. / Canada N = NOx U.S.
Residential
A=80+ AFUE Upflow/ Heating Input-Btuh
Horizontal 040 = 40,000 080 = 80,000 120 = 120,000* K=80+ AFUE Downflow 060 = 60,000 100 = 100,000 (*Available in upflow only)
SERIAL NUMBER IDENTIFICATION CODE
Production Code Design Serie Month
Residenti Year
FURNACE SPECIFICATIONS
G6RA MODEL NUMBERS: -045( 08 face -072( )12 -072( )16 -096()12 -096()16 -096( )20 -120( )16 -120( )20 -144( )20
-060( )12 Input-Btuh (a) 45,000 60,000 72,000 72,000 96,000 96,000 96,000 120,000 120,000 144,000 a
Ts [| = | « |
i ee Oe S1|S}/o| a ae Ea as a anal ee =} Beet ests , m H|=|s oO (op) @O - = v Z is To (7p) @ = > |
=
fo
+ oO 3 ze} oO = 2 Cc = oO a n oO aS) sed) D> © oO
> To) To S (e) x. 3 fe) » @O ep) >. . Te) Z. D> (co) = 1 as ° ion n
All models are 115 V, 60 HZ. Gas connections are 1/2" N.P.T AFUE= Annual Fuel Utilization Efficiency
G6RK MODEL NUMBERS -060C-12 -072C-12 -072C-16 -096C-12 -096C-16 -120C-20
(a) 60,000 72,000 72,000 96,000 96000 120,000 Heating Capacity - Btuh 48,000 58,000 58,000 77,000 77,000 96,000
> ze) Cc T ey) —- Cc a>
80+
Maximum Ext. SP - In. W.C.
Temperature Rise Range - °F
Blower D x W Motor H.P. -Speed -Type Motor FLA
Approx. Shipping Wt. Ibs.
G6RA, G6RK Service Manual 5
Clearances to Combustibles
This furnace is Design Certified by A.G.A. Laboratories, and approved by Canadian Gas Association (CGA) forthe minimum clearances to combustible material listed in Table 2. See the furnace name plate, located inside the furnace cabinet, for specific model number and clearance information.
The G6RA furnace is certified for use on wood flooring. This furnace must notbe installed directly on carpeting, tile, or any combustible material other than wood flooring.
I INVNAININ CE
Do not place combustible material on or against the furnace cabinet or within 6 inches of the vent pipe. Do not place combustible materials, including gasoline and any other flammable vapors and liquids, in the vicinity of the furnace.
G6RA Furnaces UPFLOW APPLICATION TOP
IMA
BOTTOM
G6RK Furnace DOWNFLOW APPLICATION
TOP
InN
BOTTOM
Downflow Warning (G6RK Models):
The design of the downflow furnace Is certified for natural or propane gas andfor installation on non-combustible flooring. A special combustible floor sub-base is required when installing on a combustible floor. Failure to install the sub- base may resultin fire, property damage and personal injury. The special downflow sub-bases are factory supplied accessories, part numbers 902677 and 902974. When the furnace is installed on a factory or site-built cased air conditioning coil, the sub-base is not necessary. However, the plenum attached to the coil casing must be installed such that its surfaces are atleast 1" from combustible construction. A gas-fired furnace installed in a residential garage must be installed so the burners and the ignitor are located not less than 18 inches (457 mm) above the floor, and the furnace must be located or protected to avoid physical damage by vehicles.
7 'Naey\Uni(e)\F
The Downflow Sub-base must not be installed
directly on carpeting, tile, or any combustible material other than wood flooring.
UPFLOW/DOWNFLOW INSTALLATION CLEARANCES
Vent Connector Standard Single Type B-1 Double Type Wall Metal Vent Wall Metal Vent LEFT SIDE OQ" RIGHT SIDE " VENT BACK BOTTOM TOP * FRONT
* Allow 36" minimum clearance for service.
HORIZONTAL APPLICATION TOP
INIT
BOTTOM
HORIZONTAL INSTALLATION CLEARANCES
Vent Standard Single | Type B Double Wall Wall Metal Vent Metal Vent VENT * Allow 36" minimum clearance for service.
Type BOTTOM
Connector BACK | =o”
1 0 1 0 0" 0" 4
Table 2. Minimum Clearances to Combustible Material
6 G6RA, G6RK Service Manual
Aclearance of at least 36 inches from the front of the furnace is recommended to allow for servicing and maintenance. Where accessibility clearances are greater than the minimum clearances, accessibility clearances musttake precedence.
CIRCULATING AIR SUPPLY
General
Plenums and air ducts must be installed in accordance with the Standard for the Installation of Air Conditioning and Ventilating Systems (NFPA No. 90A) or the Standard for the Installation of Warm Air Heating and Air Conditioning Systems (NFPA No. 90B).
If outside air is utilized as return air to the furnace for ventilation or to improve indoor air quality, the system must be designed so that the return air to the furnace is not less than 50°F (10°C) during heating operation. Ifa combination of indoor and outdoor air is used, the ducts and damper system must be designed so that the return air supply to the furnace is equal to the return air Supply under normal, indoor return air applications.
When a cooling system is installed which uses the furnace blower to provide airflow over the indoor coil, the coil mustbe installed downstream (on the outlet side) orin parallel with the furnace.
7 EAWNeiNiinve:
Products of combustion must not be allowed to enter the return air ductwork or the circulating air supply. Failure to prevent products of combustion from being circulated into the living space can result in personal injury or death.
All return ductwork must be adequately sealed, all joints must be taped, and the ductwork must be secured to the furnace with sheet metal screws. When return air is provided through the bottom of the furnace, the joint between the furnace andthe return air plenum must be sealed. The floor or platform on which the furnace is mounted must provide sound physical support of the furnace with no gaps, cracks, or sagging between the furnace and the floor or platform. Return air and circulating air ductwork must not be connected to any other heat producing device such as fireplace insert, stove, etc.
Ifa cooling system Is installed in parallel with the furnace, a damper mustbe installed to prevent chilled air from entering the furnace and condensing on the heat exchanger. If a manually operated damper is installed, it must be designed so that operation of the furnace is prevented when the damper is inthe cooling position and operation of the cooling system is prevented when the damper is in the heating position.
Return Air
In applications where the supply ducts carry heated air to areas outside the space in which the furnace Is installed, the return air must be delivered to the furnace by duct(s) sealed to the furnace casing, running full size and without interruption between the outside space and the one in which the furnace is installed.
y I NAWNaNiine
The solid base of the furnace must be in place when the furnace is installed with side return air ducts. Removal of all or part of the base could
cause products of combustion to be circulated into the living space and create potentially hazardous conditions, including carbon monoxide poisoning that could result in personal injury or death.
The return air ductwork may be connected to any or all of the following: left side return, right side return, or bottom return. Table 3 shows the airflow data for each furnace model. Where maximum airflow is 1800 CFM or more, two openings must be used.
G6RA, G6RK Service Manual 7
CAPACITIES —Furnace Airflow Data
Upflow Furnace Airflow Data G6RA External Static Pressure (Inches Water Column) Furnace
Model No. |___Rise | CFM _ 950
Downflow Furnace Airflow Data
G6RK External Static Pressure (inches Water Column) Furnace Motor Motor 0.1 0.2 0.3 0.4 0.5 Model No. | Speed | HP | CFM | Rise | CFM | Rise | CFM | Rise | CFM | Rise | CFM | Rise |
High * i 060C-12 Medium 1/3 43 Low ** 59 High * : 072C-12 Medium 1/3 52 Low ** 71 High * ; 072C-16 Med-High 1/2 : Med-Low 49 Low ** 58 53 096C-12 1/3 65 High * : 096C-16 Med-High | 1/2 50 Med-Low ** 58 Low 69 High * : 120C-20 Med-High 3/4 49 Med-Low** 59 Low 67
* Factory wired cooling speed tap ** Factory wired heating speed tap - Not Recommended
NOTE: Airflow rates of 1800 CFM or more require two return air connections. Data is for operation with filter(s).
Table 4. Furnace Airflow Data
8 G6RA, G6RK Service Manual
VENTING AND COMBUSTION AIR REQUIREMENTS
General
Provisions must be made in the installation of this furnace to provide an adequate supply of air for combustion. Detailed instructions for determining the adequacy of an installation can be found in the current revision of the National Fuel Gas Code (ANSI Z223.1 /NFPA54) or in applicable local building codes. Consultlocal codes for special requirements. For Canadian installations consult Canadian Installations Codes and (CAN/CGA B149.1 or.2).
If the furnace is operated with inadequate air for combustion one of the flame roll-out switches located in the burner compartment or the vent switch will open, turning off the gas supply to the burners. These safety devices are manually reset switches. DO NOT install jumper wires across these switches to defeat their function. DO NOT reset a switch without identifying and correcting the fault condition. If a switch must be replaced, use only the correct part specified in the Replacement Parts List.
Air openings in the furnace door, warm air registers, and return air grilles must not be restricted.
7 Ney ene)
Combustion air must not be drawn from a corrosive atmosphere.
Tomaximize heat exchanger life, the combustion air mustbe free of chemicals which form corrosive acidic compounds In the combustion gases. Some examples of these chemicals are chlorine, fluorine, and sulohur. Some common sources of these chemicals are detergents, bleaches, aerosol sprays, cleaning solvents, and a wide variety of commercial and household products.
When installing a furnace in a commercial building or ina laundry room or workshop of a residence, it may be necessary to provide outside air to the furnace for combustion.
TF INWENANIN eF
Furnace installation using methods other than those described in the following sections must comply with the National Fuel Gas Code and all applicable local codes to provide sufficient combustion air for the furnace.
Installation In An Unconfined Space
An unconfined space is an area including all rooms not separated by doors with a volume greater than 50 cubic feet per 1,000 Biuh of the combined input rates of all appliances which draw combustion air from that space.
Forexample, aspace including a water heater rated at 45,000 Btuh input and a furnace rated at 75,000 Biuh requires a volume of 6,000 cubic feet [50 x (45 + 75) = 6,000] to be considered unconfined. Ifthe space has an 8 foot ceiling, the floor area of the space must be 750 square feet (6,000 /8 = 750). In general, a furnace installed in an unconfined space will not require outside air for combustion. However, in “tight” buildings (with weather stripping and caulk to reduce infiltration), itmay be necessary to provide outside air to ensure adequate combustion and venting, even though the furnace is located In an unconfined space.
Installation In A Confined Space
A confined space is an area with volume less than 50 cubic feet per 1,000 Btuh of the combined input rates of all appliances drawing combustion air from that space. Furnace closets, small equipment rooms and garages are confined spaces. Furnaces installed in a confined space which supply heated air to areas outside the space must draw return air from outside the space and must have the return air ducts tightly sealed to the furnace. Aconfined space must have two openings into the space for combustion air. One opening must be within 12 inches of the ceiling, and the other must be within 12 inches of the floor. The required sizing of these openings Is determined by whether inside or outside air is used to support combustion, the method by which the air is brought to the space, and by the total input rate of all appliances in the space.
Horizontal Furnace Installation
The G6RA can be installed horizontally in an attic, basement, crawl space or alcove. It canbe suspended from a ceiling in abasementor utility room in either a right to left airflow or left to right airflow. (See Figures 1 and 2.)
Figure 1. G6RA Horizontal Installation Suspended in Attic or Crawl Space
G6RA, G6RK Service Manual 9
If the furnace is to be suspended from the ceiling, it will be necessary to use steel straps around each end of the furnace. These straps shouldbe attached to the furnace with sheet metal screws and to the rafters with bolts. The furnace could also be suspended by an angle iron frame bolted to the rafters. (See Figure 1.)
Thirty six (86) inches between the front of the furnace and adjacent construction or other appliances should be maintained for service clearance.
Keep all insulating materials away from the louvered door. Insulating materials may be combustible.
The G6RA may be installed directly on combustible wood flooring or supports, if type "B-1" vent pipe is used (See Figure 2). It is recommended for further reduction of fire hazard that cement board or sheet metal be placed between the G6RA and the combustible floor and extend 12 inches beyond the front of the louvered door.
Note: Line Contact is Permissible
qq —_——— Gas Inlet
Type “B” Vent
\____——Ss Combustible
Platform
Coil Plenum
Electrical
Supply Connection
Louver Door
Figure 2. G6RA Horizontal installation on a Platform
For venting follow the guidelines specified under the venting section.
7 IMANNAIN INCE
Furnaces installed with combustion air drawn from a heated space which includes exhaust
fans, fireplaces, or other devices that may produce a negative pressure should be considered confined space installations.
Air From Inside (See Figure 3)
If combustion air is taken from the heated space, the two openings must each have a free area of at least one square inch per 1,000 Btuh of total input of all appliances in the confined space, but notless than 100 square inches of free area. For example, ifthe combined input rate of all appliances is less than or equal to 100,000 Btuh, each opening must have a free area of at least 100 square inches. If the combined input rate of all appliances is 120,000 Btuh, each opening must have a free area of at least 120 square inches.
10 G6RA, G6RK Service Manual
Openings to
adjacent space.
Each opening must
be at least 100 sq. in. or 1 sq. in. per 1000 Btuh of total input rating, whichever is greater. See minimum area per table.
y" 2" Max. ‘7
Water Heater
Minimum Free Area (Each Opening)
100 sq. in. 100 sq. in. 100 sq. in. 100 sq. in. 120 sq. in. 140 sq. in. 160 sq. in.
Round Duct
Total Input | Diameter
Rating (Btu/hr) 40,000 60,000 80,000
100,000 120,000 140,000 160,000
Figure 3. Equipment in a Confined Space with all Combustion Air Drawn from the Inside
Outdoor Air Using Vertical Ducts
(See Figure 4)
If combustion air is taken from outdoors through vertical ducts, the openings and ducts must have a minimum free area of one square inch per 4,000 Btuh of total appliance input. In installations drawing combustion airfrom aventilated attic, both air ducts must extend above the attic insulation.
Vent or
s # Chimney
Ventilation Louvers at each end of attic
Outlet Air Duct must
be at least.1 sq. in.
er 4,000 Btuh of
otal input rating. Inlet and Outlet Ducts
a mus scene above
LIZZ attic insulation. ZZ SLD
1
Atti ag
LLL, ULE,
Inlet Air Duct must
pe a canoes Sa. in. yun of otal nut tine,
— Max 7
7
Water Heater
a. All Combustion Air from Ventilated Attic.
Minimum Free Area Round Duct (Each Opening) Diameter
10 sq. in. 4"
15 sq. in. ‘
20 sq. in.
25 sq. in.
30 sq. in.
35 sq. in.
40 sq. in.
Total Input Rating (Btu/hr) 40,000 60,000 80,000 100,000 120,000 140,000 160,000
Figure 4. Equipment in a Confined Space with all Combustion Air Drawn from the Outside through Vertical Ducts
If the unit is installed in an area with an exhaust fan, provide sufficient ventilation to prevent negative pressures from occurring in the room.
The combustion air openings must not be restricted in any manner.
Do not supply combustion air from an attic space that is equipped with power ventilation or any other device that may produce a negative pressure.
Air Directly Through An Exterior Wall
(See Figure 5)
lf combustion air is provided directly through an exterior wall, the two openings must each have free area of at least one square inch per 4000 Btuh of total appliance input.
Vent or Chimney
Each openin to outside 9
1 of total input rating.
Water Heater
Minimum Free Area (Each Opening) 10 sq. in.
15 sq. in. 20 sq. in. 25 sq. in. 30 sq. in. 35 sq. in. 40 sq. in.
Total put Round Duct Rating (Btuh) Diameter 40,000 60,000 80,000 100,000 120,000 140,000 160,000
Figure 5. Equipment in a Confined Space with all Combustion Air Drawn from the Outside through Exterior Wall
Outdoor Air Using a Crawl Space and Ventilated
Attic (See Figure 6)
When directly communicating with the outdoors, each opening shall have a minimum free area of 1 square inch per 4,000 Btuh of total appliance input. The openings shall communicate directly, or by ducts, with the outdoor spaces (crawl or attic) that freely communicate with the outdoors.
Ventilation Pours at
Vent or each end of attic
SF Chimney
Outlet Air Duct must be at least
Attic Ingulation above attic insulation.
| LZZZZ_E)
LEE
Inlet Air Duct must
AICI, TT om [wai Heater ml atl
Ventilation Louvers for
unheated crawl space Crawl Space
Figure 6. Equipment in a Confined Space with All Combustion Air Drawn from a Crawl Space and Ventilated Attic
Outdoor Air Using Horizontal Ducts (See Figure 7)
If combustion air is taken from outdoors through horizontal ducts, the openings and ducts must have a minimum free area of one square inch per 2,000 Btuh of total appliance input.
If the unit is installed in an area with an exhaust fan, provide sufficient ventilation to prevent negative pressures from occurring in the room.
The combustion air openings must not be restricted in any manner.
Vent or Chimney
Each opening to outside must pe : least
edelh er 2000 Buh icf ‘otal input rati
Air Duct
Water Heater
Minimum Free Area (Each Opening) 20 sq. in. 30 sq. in. 40 sq. in. 50 sq. in. 60 sq. in. 70 sq. in. 80 sq. in.
Round Duct
Total Input Diameter
Rating (Btu/hr) 40,000 60,000 80,000
100,000 120,000 140,000 160,000
Figure 7. Equipment in a Confined Space with all Combustion Air Drawn from the Outside through Horizontal Ducts
G6RA, G6RK Service Manual 11
VENTING REQUIREMENTS
General
This furnace must be vented in compliance with, the current revision ofthe National Fuel Gas Code (ANSI-Z223.1/NFPA54), with the instructions provided below, and with the Category | Venting Tables provided with the furnace.
In Canada, venting shall conform to the requirements of the current (CAN/CGAB149.1 or.2) installation codes. Consult local codes for special requirements.
This furnace must never be vented to a chimney flue servicing a fireplace or other appliance designed to burn solid fuel. If the furnace vent is to be connected to a chimney serving a fireplace, the fireplace must be sealed off from the chimney.
The furnace vent, if metal, may be insulated if local codes allow. Any part of the vent system, metal vent only, not exposed to weather, but which are exposed to ambient temperatures below 35° F must be insulated to prevent condensation. All vent insulation shall be foil backed fiberglass of one inch minimum thickness.
Category | - Common Venting
When an existing furnace is removed from a venting system serving other appliances, the venting system is likely to be too large to properly vent the remaining appliances.
The following steps shall be followed with each individual appliance connected tothe venting system placed in operation, while all other appliances connected to the venting system are notin operation:
(a) Seal any unused openings in the venting system.
(b) Inspect the venting system for proper size and horizontal pitch, as required in the National Fuel Gas Code, (ANSI 2223.1) or the (CAN/CGA B149 ) Installation Codes and these instructions. Determine that there is no blockage or restriction, leakage, corrosion or other deficiencies which could cause an unsafe condition.
(c) In so far as is practical, close all building doors and windows and all doors between the space in which the appliance(s) connected to the venting system are located and other spaces of the building. Turnonclothes dryers and any appliance not connected to the venting system. Turnon any exhaust fans, such as range hoods and bathroom exhausts, so they shall operate at maximum speed. Do not operate a summer exhaust fan. Close fireplace dampers.
(d) Follow the lighting instructions. Place the appliance being inspected in operation. Adjust thermostat so appliance shall operate continuously.
12 G6RA, G6RK Service Manual
(e) Testfor draft hood equipped appliance spillage at the draft hood relief opening after 5 minutes of main burner operation. Use the flame of a match or candle.
(f) After ithas been determined that each appliance connected to the venting system properly vents when tested as outlined above, return doors, windows, exhaustfans, fireplace dampers and any other gas burning appliance to their previous conditions of use.
(g) If improper venting is observed during any of the above tests, the venting system must be corrected.
(Categorie l) — Proceder comme suit pour chaque appareil raccorde a la tuyauterie d’evacuation et en etat normal de fonctionnement; tous les autres appareils raccordes a la meme tuyauterie d’ evacuation doivent etre mis hors service:
(a)sceller toute ouverture non utilisee de la tuyauterie d’evacuation.
(b)s’assurer que la tuyauterie d’evacuation presente des dimensions et une pente horizontale conformes ala norme ANSI 2223.1, intitulee National Fuel Gas Code ou aux codes d’installation CAN/CGA-B149, ainsi qu’aux presentes instructions. S’assurer que la tuyauterie n’est pas bloquee, restreinte, corrodee, qu'elle ne fuit pas et qu'elle ne presente aucun autre defaut potentiellement dangereux.
(c)dans la mesure du possible, fermer toutes les portes et fenetres du batiment, et toutes les portes entre la piece ou se trouve l'appareil raccorde a la tuyauterie d’evacuation et les autres pieces du batiment. Mettre en service les secheuses et tout autre appareil qui n'est pas raccorde a la tuyauterie d’evacuation. Faire fonctionner a regime maximal tout ventilateur d’evacuation, tel que les hottes de cuisiniere et les ventilateurs de salles de bains. Ne pas mettre en service les ventilateurs d’ete. Fermer les registres des foyers.
(d)respecter les instructions d’allumage. Mettre en service l'appareilal’essai. Reglerle thermostat de maniere ace que l'appareil fonctionne sans interruption.
(e)s’assurer qu'un appareil muni d’un coupe-tirage ne presente aucune fuite a louverture du coupe-tirage apres que le bruleur principal ait fonctionne pendant cing minutes. Employer la flamme d'une allumette ou d’une chandelle.
(f)apres avoir determine que tous les appareils raccordes a la tuyauterie d’evacuation evacuent correctement tel que prescrit ci-dessus, rouvrir les portes at les fenetres et remettre les ventilateurs d'evacuation, les registres de foyers et tout autre appareil fonctionnant au gaz a leur etat de fonctionnement initial.
(g)Siun appareil n’evacue pas correctement ala suite de l'un des essais ci dessus, corriger la tuyauterie d’evacuation.
The venting system should be designed to have the minimum number of elbows or turns. All horizontal runs shall be sloped upwards from the furnace at 1/4 inch per running foot of vent. Supports for the vent pipe must be installed a minimum of every five feet along the vent run to ensure no displacement after installation.
Under no circumstances shall any portion of the vent system extend into or pass through any return air duct, supply air duct, or plenum.
lf the furnace is operated with blocked or restricted venting, the blocked vent switch located in the vent plate will open, turning off the gas supply to the burners. The blocked vent switch is a manually reset device. DO NOT install a jumper wire across this switch to defeat its function. DO NOT reset the switch without identifying and correcting the fault condition which caused the switch to trip. If this switch must be
replaced, use only the part specified in the Replacement Parts List.
AWARNING:
Upon completion of the furnace installation, carefully inspect the entire flue system both inside and outside the furnace to assure it is properly sealed. Leaks in the flue system can result in serious personal injury or death due to exposure of flue products, including carbon monoxide.
Category Ill - Horizontal Venting
NOTE: Thereduced NOx models (eighth character N) are not approved as a Category Ill (Categorie III) furnace for use with horizontal venting.
The furnaces are approved for use with 3" single wall AL29- 4C stainless steel vent pipe in horizontal vent applications. This pipe is available from the following manufacturers: Z-FLEX Inc. - vent brand name (Z-VENT)
Heat-fab Inc. - vent brand name (Saf-T Vent)
Flex-L International - vent brand name (Star-34 Vent)
This vent pipe must be used for the entire length of the vent run. The installation must be in accordance with all instructions supplied by the vent manufacturer for use on Category III appliances. When venting horizontally this is a Category III furnace, the vent pressure is positive, and the venting system must be sealed.
For horizontal venting installations in both the United States and Canada the transition assembly must be modified, the bleed tube must be added to the pressure switch tube, and the vent switch must be by-passed. The bleed tube is found in an envelope, attached to the furnace literature.
Horizontal Venting For GGRA Models:
NOTE: An optional horizontal vent kit will be required. See Vent Kit Bleed Tube Chart on Page 40.
1. Remove the rubber tubing from the pressure switch sensor tube and the collector pan sensor tube. Cut 1/2 inch from one end of the rubber sensor tube, fold in half and cut along the bend line. Discard the 1/2 inch long piece and place the other two pieces on both ends ofthe bleed tube, do notcoverthe hole inthe bleed tube. Place the assembly back on the pressure switch sensor tube and the collector pan _ sensor _ tube. (See Figure 8.)
2. Remove the nut and restrictor plate from the vent collar assembly and discard the restrictor plate. Remove the cover plate from the envelope attached to the furnace literature, and fit the clearance hole over the weld stud. The cover plate must cover the hole(s) onthe ventcollar assembly. Tighten the nut securely while holding the cover plate in position. (See Figure 9.)
Pressure Switch
Bleed Tube Bleed Tube Orifice
Collector Pan
Figure 8. G6RA Bleed Tube Installation
3. Bypass the vent switch by removing both wires from the vent switch and attaching them to the wire nut. (See Figure 10.)
Horizontal Venting For G6RK Models:
NOTE: An optional horizontal vent kit willbe required. See Vent Kit Bleed Tube Chart on Page 40.
Looking Down at Vent Opening
Covered Vent Collar Hole
Figure 9. G6RA Vent Collar Detail G6RA, G6RK Service Manual 13
i
By-pass the vent switch, located on blower compartment door, by removing both wires from the switch. Remove wire terminals, strip wires and tie
Switch Switch Limit Flame
Roll-Out
Wire Nut
Figure 10. Limit Circuit Wiring together in a wire nut. (See Figure 11.)
Remove the rubber tubing from the pressure switch sensor tube andthe collector pan sensor tube. Cutthe tubing approximately 3" from one end and insert the bleed tube into the tubing. Do not cover the hole in the bleed tube. Place the tubing assembly back on the pressure switch sensor tube and collector pan sensor tube. (See Figure 11.)
To gain access to the restrictor plate, remove and discard the combustion tube from the transition assembly. Insure the seal between inducer and transition assembly is not broken. (See Figure 12.)
Remove and discard the restrictor plate and screw from the transition assembly. (See Figure 12.)
Install and seala4" to 3" reducer to the transition. (See Figure 13.) Attach the new high temperature vent pipe to the reducer.
a Collector
Pan
Pressure
Bleed Tube = Switch
Bleed Tube Orifice
Figure 11. G6RK Bleed Tube Installation
Combustion Tube
Remove and Discard
Screw
Restrictor Plate
The components of the horizontal vent system must not be penetrated, with screws, rivets, or other devices, either when joining pipes and fittings or using support straps. All joints * : must be sealed with high temperature silicone before locking By Inducer
Transition
Figure 12. G6RK Horizontal Vent Modification
Special 3" AL29-4C Stainless Steel Vent Pipe
4" to 3" Reducer
Transition
Figure 13. G6RK Reducer Installation
14 G6RA, G6RK Service Manual
7 Noy Ne) \F
Do not drill holes through the vent pipe or fittings on a horizontally vented furnace. Do not use sheet metal screws, or rivets. Drilling, screws, or rivets will cause leaks.
bands are installed. If the lengths of pipe must be cut, the joint must still be sealed with silicone and the locking band used. When installing the condensate tube be sure to form atrap by means of a3" loop filled with water. (See Figure 14.)
Keep the number of pipe fittings to a minimum. Maintain a minimum of 6 inches of air soace between the vent and combustibles at all times, this includes inside and outside the building.
NOTE: The direction of the male-female joints from the drain tee to the termination tee is opposite to standard gas appliance venting. The male end of the pipes point towards the furnace.
Wall Thimble (For combustible wall material)
Locking Band /,
Support Locking Band
90° Elbow \ Tee ie Sc t
Termination Tee
Outside Wall
Figure 14. Typical Horizontal Vent Installation
1. Apply anadhesive bead around the outside of the pipe approximately 1/4" from the end of the pipe. This includes the first fitting or pipe attached to the furnace.
2. Push the pipe and fitting together while twisting the pipe or fitting. Twisting the pipe or fitting soreads the adhesive completely within the fitting socket.
3. When the pipe is at the socket bottom, inspect the joint. Look foracomplete, uninterrupted ring of adhesive material around the pipe atthe fitting socket. Additional adhesive or rotation of the pipe or fitting may be required foracomplete seal. The complete adhesive material ring provides the seal required for the positive pressure vent.
4. Allventsystems must include a tee and drain plug for collection and disposal of condensate. The drain tee must be installed within the first 5 feet of vent run to protect the furnace.
5. All horizontal sections must have a slope toward the drain tee of not less than 1/4" per foot to prevent the collection of condensate at any location other than at the tee.
6. Horizontal runs mustbe supported with 3/4" pipe strap at a maximum of 5 foot intervals and at each point where an elbow is used.
7. Maintain a6 inch minimum air space to combustibles from all sections of the stainless steel vent system, except when a wall thimble is used.
Through-The-Wall Power Venting — The Tjerlund GPAK- 1TN through-wall kit is certified for use with G(-) Series furnaces. The kit includes a power venter, a side-wall vent hood and a barometric draft control. It has an electrical interlock to assure that the furnace will not operate when the power venier is off.
The kit is for use only when exhaust Is through an exterior wall, normally with horizontal vent piping. The power venter establishes negative pressure in the vent piping and the furnace operates as if connected to Category | vertical venting.
Installation Instructions are provided with the kit. Installation must conform to those instructions and applicable requirements of local codes.
Horizontal Venting (Thru-the-Wall) Venting Requirements
Furnace Pipe |Reducer | Maximu Max. Feet Model Number|Size | Needed | #Elbows| Vent Pipe
F035 G6RAT200-16 G6RAT200-20
G6RA144C-20| 3"
410 3"
Ft03"
Table 4. Horizontal Venting Requirements
G6RKO96C-16 G6RK120C-20 | 3"
G6RA, G6RK Service Manual 15
Flexible Vent Systems
WINN ANIN CE
The entire vent system must be sealed with a high temperature sealant which will withstand temperatures of 450°F. Recommended sealants: Dow Corning Sealant 736 RTV; GE 106 RTV; High Tech Ind., High TEMP RED.
Location of Outdoor Terminations Horizontal Installation
The vent termination tee must be installed with the following minimum clearances. (See Figure 15.)
Mechanical draft vent terminal
Less than 10 ft.
ot
Forced
Mechanical Air Inlet
draft vent terminal
Figure 15. Vent Termination Clearances
1. The termination tee must be 12 inches above snow level or grade level which ever is higher. See Figure 16 for alternate method to achieve 12" above snow level.
2. The minimum distance from any door, (openable) window, or gravity air inletis 4 ft. below, 4 ft. horizontally, or 1 ft. above.
3. Theventtermination shallbe aminimum of 3ft. above any forced air inlet within 10 ft. (See Figure 15.)
4. Recommended minimum distance from an inside corner formed by two exterior walls is 6 ft., but is not required.
5. Theminimumdistance from gas or electric meter(s) is 4 tt.
16 G6RA, G6RK Service Manual
10.
11.
Use Wall Thimble at Vent Points
Termination Tee
Support
[PLL / 1 eee
Figure 16. Alternate Horizontal Vent Installation
Avoid areas where condensate drainage may cause problems such as above planters, patios, or adjacent to windows where the steam from the flue gases may cause fogging. Do not terminate above any public walkway.
Selectthe point of wall penetration where the minimum 1/4 inch per foot of upward slope can be maintained. When penetrating a noncombustible wall, the hole through the wall must be large enough to maintain the pitch, pipe clearance for passage, and provide for proper sealing. Penetrating a combustible wall requires the use of awall thimble. (See Figure 22.) A 6-1/2 inch square framed opening is required to insert the thimble halves. The thimble is adjustable to varying wall thickness and is held in place by applying sealantto the male sleeve before assembly. Also run a bead of sealant around the outer wall thimble.
The vent pipe must extend 1-1/4 inches through the outer thimble half for a combustible wall. Be sure to check this carefully before cutting the vent pipe. Attach a 3 inch coupling to the end of the pipe that extends through the wall or thimble. This prevents the vent pipe from being pushed inward.
Cut an 8 inch minimum piece of vent pipe and connect the coupling to the termination tee. The inside of the tee must be a minimum of 12 inches from the outside of the wall. (See Figure 17.)
Inside Outer Overlapping Combustible ———_y Shield 61/2" Dia. Wall
Wall Thimble (Inner Half) 3" Vent Wall Thimble Outer Half
¥ oa Band
a
Protective
Overlappin Inner Shield 41/2" Dia.
Inside Combustible >
g Shield 63/s" Dia. * Termination Tee 12" Min | Wall a Outside
Combustible Wall
Figure 17. Typical Termination
Flexible gas vent is approved for use in vertical single vent orcommon ventinstallations only. The minimum distance to combustibles is 1" for type B insulated and 6" for single wall. The venting system must be installed in accordance with the local authorities, the vent manufacturer's instructions and the instructions listed below.
The flexible vent must be installed in accordance with the venting tables for vertical or common venting only. The vent system must be supported in horizontal runs with 3/4" pipe strap ata maximum of 5 footintervals. All horizontal sections must have a slope toward the furnace of not less than 1/4" per foot. The vent must not sag, orhave any bends greater than 90 degrees.
Leak Check After the gas piping to the furnace is complete, all connections must be tested for gas leaks. To check for leaks use only a soap and water solution or other approved method.
NOTE: When pressure testing gas supply lines at pressures greater than 1/2 psig (14 in. water column), the furnace must be disconnected from the gas supply piping system to prevent damage to the gas control valve.
If the test pressure is less than or equal to 1/2 psig (14 in. water column), the furnace must be isolated from the gas supply line by closing off the main shut-off valve.
ELECTRICAL WIRING
General
Electrical connections must be made in accordance with all applicable local codes and ordinances, and with the current revision of the National Electric Code (ANSI/NFPA 70).
For Canadian installations electrical connections and grounding must be done in accordance with the current Canadian Electrical Code (CSA C22.1 Part 1) and/or local codes. If any of the original wire as supplied with the furnace must be replaced, it must be replaced with wire having a minimum temperature rating of 105°C. Refer to the furnace nameplate and Table 7 for electrical requirements.
SYSTEM OPERATION INFORMATION
General
Proper maintenance is most important to achieve the best performance from a furnace. Follow these instructions for years of safe, trouble free operation.
¢ Do not place combustible material on or against the furnace cabinet or the vent pipe.
¢ Do not store gasoline or any other flammable vapors and liquids in the vicinity of the furnace.
¢ Change or replace the air filters monthly during any period when the circulating blower is operating regularly.
¢ Always replace the doors on the furnace after servicing. Do not operate the furnace without all doors and covers in place.
¢ Avoid operating the furnace when windows and doors are open.
¢ Be sure that the thermostat is properly installed and is not being affected by drafts or heat from lamps or other appliances.
Sequence of Operation
Operating sequences forthe heating, cooling, and fan operation are described below. Refer to the wiring diagrams (Figure 22, Page 22 & Figure 23, Page 23) andthe low voltage field wiring diagram (Figure 28, Page 25).
Heating Mode:
1. Onacallforheatthermostat closes, applying 24 VAC to the W terminal on the control board.
2. Thecontrol board checks for continuity on the 24 VAC limit control circuit (over-temperature limit switch, flame roll out switches and blocked vent switch). If an open limit is detected the control board will energize the inducer and the conditioned air blower. All other system functions will be inoperable until the limit circuit closes. While the limit is open, the red LED will pulse at a rate of one blink.
3. The furnace control checks for continuity across the pressure switch (24 VAC). If the pressure switch is closed the heat mode sequence will not continue. If it remains closed for 10 seconds the red LED will blink 3 times repetitively until the fault condition clears.
4. The inducer is energized.
5. The pressure switch will close. If the pressure switch does not close after 10 seconds the fault LED will blink 2 times repetitively and the inducer will continue to run until the switch is closed.
6. The inducer will pre-purge for 30 seconds and then the ignitor will start its warm-up. After 30 seconds of ignitor warm-up the gas valve (24 VAC) will open. The ignitor circuit stays energized for 6 seconds after the gas valve opens.
G6RA, G6RK Service Manual 17
7. The furnace control must prove flame via the flame sensor six seconds after the gas valve opens. If flame is sensed, all burners are on and the ignitor cools off. If no flame is sensed, the gas valve closes immediately and the inducer continues to run. A second trial for ignition (step 6) begins if no flame is sensed. On the fifth try for ignition, the furnace control is locked out and the red LED will blink 4 times repetitively. The thermostat must be opened for at least ten seconds to reset the furnace control after a lock out. Otherwise, the furnace will attempt another ignition Sequence in 1 hour.
8. The furnace control energizes the circulating air blower on the heating speed 30 seconds after the gas valve circuit is energized.
9. Whenthethermostathas been satisfied, gas valve is de- energized.
7 'Naney \Un ie) \F
Do not use matches, lighters, candles or other sources of open flame to check for gas leaks.
7 \Naey \Un ie) \F
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation.
Verify proper operation after servicing.
10. The inducer is de-energized after a 30 second post purge.
11. The furnace control keeps the circulating air blower energized for 120 second (factory set) or 60, 90, or 180 seconds (field adjustable). (See Figure 21.)
12. Abnormal conditions: If a limit opens during operation, the inducer and circulating air blower continue to operate. The gas valve is de-energized immediately. The blowers continue to operate until the limit closes. When the limit closes the induced draft motor will run through post purge. The circulating air blower continues to operate for the specified delay (factory set at 120 seconds).
Cooling Mode:
1. Onacall for cooling the thermostat closes, applying 24 VAC to the Gand Y terminals onthe furnace control. This closes the compressor contactor.
2. Thefurnace control energizes the circulating blower (115 VAC) on the cooling speed.
3. When the thermostat is satisfied, the G and Y terminals on the control board are de-energized opening the compressor contactor.
4. The circulating air blower is de-energized after a 90 second delay.
18 G6RA, G6RK Service Manual
Fan Mode:
1. On acall for fan operation, the thermostat applies 24 VAC to the G terminal on the furnace control board.
2. Thecirculating air blower is energized immediately on the heating speed.
3. Ifthe furnace is operated in the continuous ON position at the thermostat and is then switched to AUTO, the circulating blower will operate for a specified delay (factory set at 120 seconds).
Furnace Fails to Operate lf the furnace does not operate check the following:
Is the thermostat operating properly?
Are the blower compartment door(s) in place?
Is the furnace disconnect closed?
Has the circuit breaker tripped or the control board fuse burned open?
Is the gas turned on?
Are there any manual reset switches open?
Is the filter dirty or plugged?
Is the flame sensor coated? (Remove and clean with steel wool.)
NS
ON HAM
lf the furnace locks out after 5 attempts for ignition, it will try again every hour if a call for heat remains. If the inducer and circulating air blowers are operating, and items 1 through 8 have been checked, press the red reset button on the vent safety switch. (See Figure 19.) If the furnace operates after depressing the reset button, contact a qualified serviceman to identify and repair the problem.
If the furnace continues to not operate, depress the red reset button on the flame roll out switches. (See Figure 19.) If the furnace operates after depressing the reset buttons, contact a qualified serviceman to identify and repair the problem.
Twinning of Two Furnaces
The control board on a G6 series furnace is capable of being twinned to another G6 furnace. The thermostat wires andthe 3/16 inch quick-connect terminals marked "TWIN" on the furnace controls must be connected together for twinning. (See Figure 18.)
NOTE: Components are listed in order of sequence of operation.
Thermostat
WGYR O10 0:0
Ignitor
Flame Sensor Gas Valve Roll-Out Switch(s) Pressure Switch Control Board Blower Door Switch
Twin Terminal
Figure 18. Twinning
Vent Assembly (G6RA) Vent Switch
Low Voltage Transformer
Burner Assembly Supply Air Limit Switch
Figure 19. Component Parts
Twin Terminal
Blower Assembly Inducer Combustion Tube w/insulation (G6RK) Vent Transition Assembly (G6RK)
G6RA, G6RK Service Manual 19
Line Voltage Wiring (See Figure 15)
The line voltage (115 volt) to the furnace must be supplied from a dedicated circuit containing the correct fuse or circuit breaker for the furnace. See Table 5. An electrical switch should be readily accessible from and within sight of the furnace. Allline voltage connections must be made within the furnace, or in a junction box.
The furnace cabinet must have an uninterrupted, unbroken ground to minimize injury should an electrical fault condition occur. The controls used in this furnace also require an earth ground to cooperate properly. Acceptable methods for grounding are electrical wire or conduit approved for electrical ground service. Do not use gas piping as an electrical ground.
NOTE: Proper line voltage polarity must be maintained in order for the control system to operate correctly. Verify that the incoming neutral line is connected to the white
Furnace | Furnace | Cabinet}; Nominal Model Input Width | Electrical Number | (Btu/hr) (in.) Supply Voltage G6R(A,K)
Maximum | Minimum |Maximum| Minimum Operating | Operating | Furnace
wire and the incoming "hot" line is connected to the black wire in the furnace junction box. The G6 series furnaces will not operate unless polarity and ground are properly connected. (See Figure 24.)
Never use gas lines as ground.
To determine polarity, the incoming power supply should be checked. The "Hot" lead will read 115V to ground. The "neutral" should read OV to ground.
Supply Voltage
Supply voltage to the furnace should be nominal 115 volts. It mustbe between 103 volts and 127 volts. Supply voltage to the furnace should be checked with furnace in operation. Voltage readings outside the specified range can be expected to cause operating problems. Their cause MUST be investigated and corrected.
Maximum Wire Fuse or Circuit
Voltage | Amperes| Gauge | Breaker Amps**
045(*)-08
45,000 60,000 72,000 72,000 96,000 96,000 96,000 120,000 120,000 144,000
115-60-1 115-60-1 115-60-1 115-60-1 115-60-1 115-60-1 115-60-1 115-60-1 115-60-1 115-60-1
Thermostat Wire Gauge
Field Supplied Fused Service
Panel =
Field Supplied Disconnect Within
Field Supplied
Recommended Thermostat Wire Length 2-wire 4 or 5-wire (heating) (cooling)
Table 5. Electrical Data
Field Line Voltage Wiring
Factory Line Voltage Wiring
a = Ground
Sight of Furnace
Figure 20. Line Voltage Field Wiring
20 G6RA, G6RK Service Manual
Troubleshooting Flow Chart Use in conjunction with time sequence and wiring diagrams that follow.
Inducer starts
Call for heat, t-stat closes R-W
No
Yes
Check fuse on
24 Volt, C to W ] No Check for red light No circuit board,
on circuit board on circuit board
Yes replace if no continuity Beceect ee Is light blinking closes within 5 times? 10 seconds ies Yes
Polarity is reversed
Switch L1 & L2
Inducer prepurges for 30 seconds
hs
Ignitor heats up and glows for 30 seconds
\"
Gas valve open Yes
Do Burners Light Yes
Note: Retry <—— _ Will retry 4 more times. <——
Every Soft lock out blinks 4 times
Hour on status light. Power down and back up to reset.
Burners stay on longer than 6 seconds Yes
Ignitor turns pff 7 seconds after gas yalve opens
Yes
Main blower starts after delay time (30 seconds)
Yes
No_, Check for voltage No__, Circuit board 3 blinks at inducer molex plug Yes Yes |
Replace ~«N® Pressure switch Board stuck closed
Replace Inducer Blower
per nots Circuit board blinks 2 times Replace bee pressure switch No — Pressure switch Isthere>12mAonWterminalofcircuit open board? Replacet-stat oraddisolation relay Yes No : Greater than —_ {Check venting -.75" W.C. differential at pressure switch Yes
Replace pressure switch
Levee Check for voltage nos Replace circuit board
at molex plug Yes
Replace ignitor
No, 24 volts at gas valve. Insure lever is in ON position. Insure gas inlet pressure is below 14" W.C. Yes
Replace gas valve
No Manifold Gas No Pressure Available
Yes
Check and adjust ignitor gap to 3/16"
Clean flame sensor with steel wool. Check ground circuit to Furnace.
Flame light blinks at 1 uA(weak signal)
No Flame light on
| Yes
Replace board
Flashing
No __, [Replace circuit board
No Check for voltage at No
com and heat terminals 7 Replace circuit board
pie
Check motor and capacitor
Flame, inducer, main blower stay on until call for heat ends
G6RA, G6RK Service Manual 21
Event
T'stat On Call For Heat (R to W)
Vv Inducer
pon
Norma! Shut-down:
Start-up / Shut-Down
stat Off (Break R to W)
Main Blower
Main Blower Flame |FProvin
i Gas, Valve Factory Set At
(Adjustable To 60, 90, 180)
Inducer
Elapsed Time Line - Sec. NORMAL SHUT-DOWN SEQUENCE
Normal Start-up:
1. Close R to W circuit. The inducer motor is energized.
2. After a 30-second pre-purge the igniter is energized.
3. After a 30-second heat-up period the gas valve is energized (the igniter remains on during the first 6-seconds. The gas vaive will be de-energized at 7-seconds if flame is not proved).
4. Afier 30-seconds the main blower is energized (Total elapsed time is 90 sec.}.
1. Break R to W circuit. The gas valve is immediately turned off. 2. After 30-seconds the inducer is turned off. 3. After 90-seconds the main blower is turned off (120-seconds after gas valve}.
120 Sec. —-—----
lisp eeeete a oh aiee pes ee ee ee cea
Figure 21. UTEC Control Sequence
22 G6RA, G6RK Service Manual
For G6RA Residential
oo} BLUE a BLUE CY eo L) CO
VENT ROLL-OUT SWITCH SAFETY SWITCH
AIR CONDITIONER
Furnaces
e 'e e e O) e ) eo ) ‘eo
FLAME FLAME BLOWER SUPLY AIR PRESSURE ROLL-OUT ROLL-OUT DECK LIMIT SWITCH SWITCH SWITCH SWITCH SWITCH (optional) (optional) (optional)
JUNCTION
BLOWER OFF o =)
VPIITE (HEIR aetona teed gna heel ice ea el al ieee en eheeetenerearts BOK BLACK 120V - -----------P--------b de Pde eee ee eee ee eee eee eee GROUND 2aeece coset eee eer eet Senet an eeaneeeeceee Vee ROOM THERMOSTAT
6 TRANSFORMER WHITE W/ BLK STRIPES
© waar ;
er } 24 ! BLK W/ WHITE STRIPES
@ 1 i} 1 i}
CONDENSING UNIT
FLAME SENSOR
— ED
YELLOW
———
3JWV 14
SNLVILS
3 OR 4 SPEED MOTOR
_freoras
——EAC — HUM
INDUCER
MOTOR PLUG STATUS RED If any of the original wire as supplied FAULT CONDITION LIGHT _ | with the furnace must be replaced, it
pPowerOn————~—~—SC*d «CON __| must be replaced with wiring material
Limit Circuit Open 1 FLASH | having a temperature rating of at least 105 C.
Pressure Switch Stuck Open 2 FLASHES
Pressure Switch Stuck Closed
Legend
Ignition Failure (Check Ground)
115 VAC & Neutral Reversed or no Ground
False Flame or Gas Valve Relay Shorted Continuous Power Off
FAULT CONDITION
Field Wiring -—-—-— Factory Wiring:
Low Voltage High Voltage
FLAME YELLOW LIGHT
Low Flame Sensor Signal Continuous Flash
Flame Present
ON
Figure 22. G6RA Integrated Control Board System Diagram
G6RA, G6RK Service Manual 23
WD#703768
For G6RK Residential Furnaces
VENT BLOWER SUPPLY AIR FLAME PRESSURE SAFETY DECK LIMIT ROLL-OUT SWITCH SWITCH SWITCH SWITCH SWITCH
BLUE
WHITE BLACK
Lo se ee ORANGE : yD I 1 m 1 ' m 1 1 2 | i —
w - Oo = m ms) w) .e) Oo =) i) = = oO <
C) Sloe eo TRANSFORMER WHITE W/ BLK STRIPES
C) eet eS 24V 120 V ( ) a BLK W/ WHITE STRIPES (=) =e
BLOWER OFF o °o
AIR CONDITIONER CONDENSING UNIT
BLACK
FLAME SENSOR — |
3 OR 4 SPEED MOTOR RED
YELLOW
WHITE
BLUE a BLACK a
WHITE 6 |
INDUCER
WD#703769
Figure 23. G6RK Integrated Control Board System Diagram
24 G6RA, G6RK Service Manual
Polarity may be verified as follows:
. Turn power supply "QN“
. Using a Voltmeter check for voltage between the Hot (Black) and Neutral (White) wire of supply circuit.
» Reading should be Line (Supply) Voltage.
- Check for Voltage between the Neutral (White) wire and Ground wire of the supply circuit.
. Reading should be zero Volts. {if fine voltage is read, polarity is raversed}
. A zero Volt reading indicates there is no voltage potential on Neutral wire.
. Double check by checking for voitage between the Hot (Black) wire and Ground wire of the supply circuit.
. Reading should be Line (supply) Voltage. (if zero volts is read, there is no ground, or polarity is reversed.)
, HUT NEUTRAL
Figure 24. Polarity and Ground
Polarity and Ground
The G6 furnace will not operate if loss of ground occurs. Every effort should be made at the installation to provide a good ground. If old 2-wire romex exists it should be replaced with a 2-wire w/ground. A cold water line could be used provided that the connection or grounding occurs before any di-electric fittings and provided no plastic pipe is used inside or outside the building.
Blower Door Switch
The blower door switch is located near the center of the furnace. (See Figure 25.) The switch is normally open and closes with the proper installation of the bottom door of the upflow models or top inside blower door on downflow models.
lts purpose is to break the 115 vac power supply when the door is removed exposing the blower.
Figure 25.
Check-out procedure (using ohm meter).
Turn off incoming power supply.
Disconnect the wires on the switch.
With the switch at rest, no continuity should be read. Now depress the switch plunger, the OHM meter should show continuity or 0 ohms. If not, replace switch.
The switch can also be checked with the 115 vac power supply on. If the switch is manually depressed and 115 vac is read across it, then the switch is bad and mustbe replaced.
a Nee
Transformer (See Figure 26)
The transformer supplies control voltage (24 vac) by stepping down the supply (primary) voltage from 115 vac to 24 vac (secondary voltage). Transformers are rated by VA. VAis the volt/amp or total wattage the secondary can handle. Whena transformer is replaced the VA should be of an equal or greater value.
ty
Figure 26.
G6RA, G6RK Service Manual 25
Check-out procedure:
_—h
Using a volt/ohmmeter on at least 115 vac scale.
2. Measure the voltage on the control board terminals "XFMR" & "NEUTRAL".
3. If voltage is 115 vac measure the voltage at terminals marked "24 vac" & "Com" located in the center of the control board.
4. If115vacis measured at"XFMR" & "NEUTRAL" but no voltage is present at"24 vac" &"Com" replace transformer.
Transformers open on primary indicate low voltage short
circuit. Transformers open on secondary indicate an overload
(a current draw that exceeded rating).
Low Voltage Wiring
Figure 27.
Install the thermostat per the manufacturer's instructions. The low voltage (24 vac) connections from the thermostat are made atthe terminal strip on the control board in the furnace. See Figure 23 for the proper connections for heating only (two-wire) and heating/cooling (four-wire) applications. The recommended minimum wire gauge for thermostat wiring is shown in Table 5, on page 19.
The thermostat must not be installed on an outside wall or any other location where its operation may be adversely affected. Adverse effects include radiant loading from fireplaces, sunlight, or lighting fixtures, and convective loading from warm air registers or electrical appliances.
To check the heat anticipator setting: Jump out R to W at thermostat with 10 Loop Helix and
measure current draw after blower starts. Divide by 10. Example: 4 Amps = .4 set at .4.
26 G6RA, G6RK Service Manual
A/C Condensing Unit ae
ondensing Unit Control Box
3388 Blower Off [ram 1] Timing
TWIN
Connect R&W For Heating Only
Flame Signal Light (Yellow) e
Status Light Red Room nee)
Thermostat
Unused Motor Leads
INNH OVS
FIELD WIRING
Low Voltage Connections
Figure 28. Low Voltage Field, Four-wire Heating/Cooling Applications
OR
Set the heat anticipator at approximately .5.
Control Board (See Figure 24)
The control board is manufactured by UTEC. This control manages all furnace functions. It also serves as a diagnostic
tool if the furnace should malfunction.
Features:
Figure 29.
90 second delay blower "off" time in cooling mode. Low Voltage Fuse - an over-current, short circuit safety device designed to protect the control board in the event of a low voltage short or over-current. (See Figure 30.) Field Adjustable Fan Settings (Heating Mode)
Figure 30.
The off times are field adjustable and may be set from 180, 120, 90,60 seconds; 120 being set from the factory. To change the off-time, remove jumper pin and replace it on the desired time. Time-on is fixed at 30 seconds. (See Figure 31.)
Hig ae Juli er
qos 014
a To |
if Tr - T Figuié 31.
D. Humidifier & Electronic Cleaner Tap - Bothtaps are rated
at 1 amp and have an output voltage of 120 VAC. All humidifiers and electronic air cleaners should be installed per the installation instructions the manufacturer supplied with their equipment. (See Figure 32.)
Note: A 24 volt humidifier solenoid coil must not be wired across the "W" and "C" terminal. This will interfere with the operation of the control board and may influence the heat anticipator in the thermostat.
Figure 32.
E. Twinning Terminal - The function of twinning is to insure
simultaneous blower operation on two furnaces. The G6 series is twinning ready. The 3/16" quick connectterminal on the board must be connected to the other furnace control. The thermostat wiring is provided inthe diagram. See Figure 33 for location and Figure 18 on page 18 for Twinning Diagram.
Figure 33.
F. Diagnostic Lights - the diagnostic light feature is to aid
the service technician in identifying the nature of the eee See Figure 33. Red Status Light. An explanation of the flash code may be seen on the inside of the door. Note: The light must be observed before the bottom door is removed since the board does not store the fault condition in its memory. See Table 6.
2. Yellow Flame Light. This will come on solid with a
flame signal of 1uA or more. The flame light will blink atthe point of aweak signal and go out at any reading of .5uAorless. See Flame Sensor section on page 34.
G6RA, G6RK Service Manual 27
No. of Flashes
Fault Condition
No Fault LED on
Limit Circuit open
Pressure Switch stuck open
Pressure Switch stuck closed
Ignition Failure (Unit will try 5 times for ignition)
Polarity or Ground False flame or
Gas Valve Relay Shorted
Continuous Flash
Power Off LED off
Fault Clearing
Status of Furnace
Normal
Main Blower & Induced Draft
Motor running Limit Circuit closes
Induced Draft
Motor running Pressure Switch closes
Unit does not operate Pressure Switch opens
Unit does not operate Auto-reset after one hour
Unit does not operate Reverse Polarity,
Reestablish Ground
Main Power or Thermostat resets
Both fans operate
Table 6. Status Light Conditions
High Limit Controls
The G6 (RA/RK) series incorporates 3 different types of limit controls: (See Figure 34) a main limit control which is located inthe heat exchanger front panel, a vent limit control located on the inducer housing, and 1 roll out switch on top of the burner box on G6RK. G6RA will have one on the left side, one on the right side, and one on top of the burner box.
Auto Reset
Figure 34.
28 G6RA, G6RK Service Manual
Alllimits are in series with each other and are between #3 and #8 pins on the nine pin connector that plugs into the control board. Limit controls are normally closed switches, that open thermostatically to prevent furnace operation in unsafe temperature conditions.
Main Air Limit Control (See Figure 35)
The main limit control is an automatic reset type. It reacts to abnormally high air temperatures in the heat exchanger area. Ifthe main limit opens, the gas valve is de-energized and the induced draft and main blower motors continue to run. The main limit will automatically reset after the temperature is reduced.
Figure 35.
Check-out Procedure:
1. Shut off power to furnace. 2. Remove wires from limit (Be sure furnace has removed any heat surrounding switch). 3. Check for continuity across switch. a. _ Ifcontinuity is present, switch is closed and assumed good. b. — Ifcontinuity is infinite, the limit is open and should be replaced.*
*Limits should be replaced with their exact replacement.
Check-out can also be performed using a voltmeter: a. Put meter on at least 24 vac scale. b. A voltage reading across the switch indicates an open switch if there is voltage
present at the switch.
Possible causes for Main Limit Tripping:
Dirty filter
Dirty cooling coil
Oversized furnace
Restrictive duct system
Main blower failure
Improper speed selection
Over-firing of furnace (gas pressure too high)
Main or induced draft motor cycling on internal overload
C2. OO Ne
Vent Limit Control (See Figure 35A)
The function of the vent limit switch is to sense the heat from the flue gas in the event the vent system becomes blocked or restricted.
Check-out Procedure: Same as for main limit switch. Possible causes of vent switch tripping:
1. Blocked vent system.
2. Improper installation of special vent systems.
3. Inadequate combustion air. Furnace may be operating in a space classified as "confined." Consult Section 2 of this service manual.
Figure 35A.
G6RA, G6RK Service Manual 29
Roll Out Limit Control (See Figure 36)
The function of a roll out switch is to sense any flames backing out of the heat exchanger tubes. They are normally closed and are manually reset.
Check-out Procedure:
Shut off power supply to furnace.
Remove wires from roll out switch.
Using an ohmmeter, check out continuity across switch. An infinite reading indicates an open switch.
Depress reset button to reset switch.
Continuity or 0 ohms should now be read. If not, replace switch.
OO el
Possible causes of roll out switches tripping:
Blocked heat exchanger (sooted)
Loose heat exchanger tube
Burner misaligned
Supply air interfering with flame patterns Overfiring/too high gas pressure Insufficient combustion air
OO lS
Figure 36.
Draft Inducer Motor (See Figure 37.) All models use an induced draft combustion blower mounted Pressure Switch
onthe outlet of the heat exchanger. Its purposeisto establish The pressure switch verifies that the inducer is drawing the a draft (flow) through the heat exchanger, to insure that all flue combustion gases through the heat exchanger. (Figure 39.) products are carried outside the structure via the vent pipe. (See Figure 40.) The blower is driven by a 115V permanent split capacitor motor. The same (part #) blower is used on all models of all series.
Check-out Procedure:
1. Disconnect Molex plug between control board and motor.
2. Using the appropriate scale on avolt meter, insert probes into plug coming from control board.
3. Establish call for heat.
4. \Ifvoltage is read, check fan capacitor. If fan capacitor is okay, replace motor. (See Figure 38.)
5. Ifno voltage is read, replace control.
6. Check for debris in wheel preventing it from turning.
Figure 39.
30 G6RA, G6RK Service Manual
Once the ventor motor builds up to speed, and under normal operation conditions, sufficient (negative) pressure will be created to close the pressure switch, and keep it closed for the whole heating cycle. Under abnormal conditions, such as ventor motor failure or restricted vent pipe, or leak around ventor assembly, sufficient negative pressure will not be created. This condition will cause a 2 flash fault code on the board and ignition will not take place.
Exchanger
Under most circumstances, when the pressure switch is not closing, sufficient (negative) pressure is not being created.
To test for proper negative pressure, install a negative pressure gauge (magnehelic or equivalent) or U Tube as shown in Figure 41. Follow check-out procedure. If sufficient negative pressure is being created, reading is steady, and vacuum hoses are Clear, replace pressure switch. If sufficient negative pressure is not being created, look for problems described in Table 8.
Exhaust Blower
Air Flow through Heat Exchangers
Burner Compartment
Figure 40.
Open Close Application Nordyne Part # Switch Type
-0.55 -0.75 80+ upflow 632212 atm.-single port (NO) -0.55 -0.75 80+ downflow 632212 atm.-single port (NO
*G6RD vent pressure switch is normally closed
Table 7.
G6RA, G6RK Service Manual 31
Check-out Procedure: 2. Connect a Differential Pressure Gauge or Inclined
1. Remove orange wires from pressure switch. Place atee Manometer to tee. in the hose connecting pressure switch to the inducer 3. Start induce draft motor. housing. 4. Negative pressure created by the induced draft motor must be greater than 0.75" W.C. for switch to close. (See
i oe aj - ,- Table 7.)
5. Use anohmmebter to check for continuity across switch.
6. Ifcontinuity is established, switch is closed. If ohmmeter shows an infinite reading, switch is open, and must be replaced.
a
lf the pressure reading will not pull down to 0.75" W.C., then there could be several reasons why:
Vent blockage.
Heat exchanger blockage.
Poor seal on collector box to induced draft motor. Bad blower wheel in induced draft motor.
Crack or hole in heat exchanger.
anata ee
The switch must be open to be ready for the next heating cycle. If switch remains closed, a flash code of 3 will be produced by the control board.
Figure 41.
Lower (Lesser) Negative Pressure Than Closing Pressure Lower than normal negative pressure measured at the combustion blower may be caused by:
Restriction on outlet side of combustion blower (blocked flue, debris or venting not properly supported or sloped)
Leak (lack of restriction) on inlet side. Inducer inlet leaking, inducer blower wheel loose, or leak in heat exchanger.
To test for restriction in vent pipe to verify problem is outside of furnace, disconnect vent for test period only and start furnace. If furnace starts, look for problem in vent pipe. Reconnect after testing.
Table 8. Lower (Lesser) Differential Negative Pressure Than Closing Pressure
32 G6RA, G6RK Service Manual
Hot Surface Ignitor (See Figure 42.)
The hot surface ignitor is helical in shape and is located approximately 3/16" in front of the burners. Its function is to ignite fuel at the appropriate time in the sequence. The hot surface ignitor used by NORDYNE is manufactured by CARBORUNDUM.
NOTE: Special care shouldbe taken when handling the ignitor. You should never touch the ignitor surface. Grease or dirtfrom your hands will shorten the ignitor's life.
Figure 42.
Check-out Procedure:
1. Unplug ignitor from 2-prong plug.
2. Place avoltmeter on the proper scale (at least 115 vac).
3. Establish a call for heat.
4. Afterapprox.30 seconds ofinduced draft motor operation,
the ignitor should see line voltage.
If voltage is present, replace the ignitor. (See Figure 43.)
If no voltage is present, replace control board.
The ignitor may also be ohmed out. The ignitors usually
range from 125 to 150 ohms at 70°F/21°C. (See Figure
44.)
8. Be sure when replacement ignitor is installed that it is approximately 3/16" from the burners. Mishandling and misalignment are reasons why the ignitor could fail.
NO
Figure 43.
Figure 44.
G6RA, G6RK Service Manual 33
Gas Valve (See Figure 45.)
The G6 series furnaces use Honeywell valve VR8205A2008. Gas valves are 24 vac operated. There are ports on the valves to read incoming supply pressure and manifold or burner pressure. Supply pressure for natural gas should be 5- 7"W.C.LP gas should be 11-13" W.C. Manifold pressure for natural gas should be 3.2" W.C. (see Figure 46) and LP gas should be 10" W.C. (see Figure 45).
i | | | .
Figure 46.
34 G6RA, G6RK Service Manual
Check-out Procedure
ie
2. 3.
By using a volt meter on a 24 volt scale, position the probes at the gas valves.
Establish a call for heat.
After furnace has operated for approximately 60 seconds, the gas valve receives 24 vac from the control board. (See Figure 47.)
lf gas valve does not open, verify gas inlet pressure is available and not above 14" W.C., then replace valve. Note: High inlet gas pressure will lock down valve. Voltage may also be checked at the control board.
If voltage is not available at the control, replace control.
Gas valves have a resistance of 1.9 to 2 mega ohms. This coil may be open or shorted.
Figure 47.
Adjusting Manifold Pressure
I
Sl a Seo
With gas valve in the off position, remove the outlet pressure cap screw using a 3/16" Allen wrench. Connecta U-tube manometer or gauge to read pressure. Turn on gas valve and establish call for heat.
Read pressure on U-tube manometer or gauge.
Adjust pressure as necessary:
a. 3.2" W.C. for natural gas
b. 10" W.C. for LP gas
If an adjustment is needed, remove pressure regulator cap. Turn the adjustment screw clockwise to increase pressure and counterclockwise to decrease pressure. Replace regulator cap and shut off valve to remove U- tube or gauge. Reinstall pressure cap screw.
Flame Sensor (See Figure 48.)
The flame sensor is located in front of the first burner. After the burners are ignited, flame is proven through the flame sensor by flame rectification. The sensor is an alloy consisting of aluminum, chromium, and iron. This alloy is commonly known as Kanthal D.
Figure 50.
Studies have shown that silicone oxides may accumulate on the sensor. It is important that the furnace operates in an environment which is conducive to proper furnace operation. These oxides can be removed by brushing with steel wool.
Figure 48. Heat Exchanger and Its Components
The G6 uses a tubular type of heat exchanger made from aluminized steel. (See Figure 51.) Inside the heat exchanger are the tubulators, located in the last passage of each tube, behind the collector box. They help in the efficiency of the combustion process. (Figure 52.)
Check-out Procedure:
1. Use amicro amp meter or the micro amp setting ona digital volt/ohmmeter to measure the flame current signal. (uA scale.)
Disconnect flame sensor atthe push-on connector below the burner assembly.
Put meter probes in series with flame sensor connectors. Establish a call for heat.
After flame is established, note micro amp reading.
A strong signal is 3 to 4 uA. (See Figure 49.) The board will close the gas valve if the micro amp reading is less than 0.5 UA.
Nh
OL
Figure 49.
7. Toaidintroubleshooting, the ignition control has a yellow flame signal light. If the light is on, flame signal is at 1 or higher micro amps. Ifthe light is blinking, signal is below 1 UA and is weak.
Reasons for Poor Micro Amp Readings (See Figure 50.)
1. Dirty flame sensor.
2. Poor positioning of flame sensor. 3. Poor ground on furnace.
4. Lowgas pressure.
5.
High gas pressure.
Figure 52.
G6RA, G6RK Service Manual 35
BLOWER PERFORMANCE
Proper Airflow - Checking Temperature Rise. (See page 7.) A temperature rise may be taken across the furnace by checking the temperature of the supply duct and subtracting the return air temperature.
If the temperature rise is too high, air flow must be increased by increasing blower speed or removing any restriction to airflow. If temperature rise is too low, air flow is too great. Reduce air flow by using a low speed on the blower.
Causes for excessive temperature rise:
Dirty air filter
Oversized furnace (undersized duct)
Blower speed too low
Dirty evaporator coil
Overfired furnace due to too much gas pressure
oa SN
FLUE GAS TEMPERATURE
The G6 series furnaces flue gas temperature range is between 300°F and 325°F Make asmall hole in vent pipe, as close to furnace as possible. Insert temperature probe and note temperature.
Possible causes for high flue gas temperatures: 1. Too much gas pressure
2. Not enough air flow across furnace
Low flue gas temperatures may be attributed to: 1. Too little gas pressure
2. Too much air flow
3. Very low return air temperature
After flue gas has been measured, reseal vent pipe.
Natural Gas Pipe Capacity Table (CU.FT./HR.)
Capacity of gas pipe different diameters and lengths in cu. ft. per, hr. with pressure drop of 0.3 in. and specific
gravity of 0.60 (natural gas).
Nominal Length of Pipe in Feet lron Pipe Size, Inches 10 20 30 40 50 60 70 80 1/2" 132 92 73 63 56 50 46 43 3/4" 278 190 152 130 115 105 96 90 1" 520 350 285 245 215 195 180 170 1 1/4" 1,050 730 990 300 440 400 3/0 350 1 1/2" 1,600 1,100 890 760 670 610 960 030
After the length of pipe has been determined, select the pipe size which will provide the minimum cubic feet per hour required for the gas input rating of the furnace. By formula:
Cu. Ft. Per Hr. Required
Gas Input of Furnace (Btu/hr)
Heating Value of Gas (Btu/Ft3)
The gas input of the furnace is marked on the furnace rating plate. The heating value of the gas (Btu/Ft3) may be determined by consulting the local natural gas utility or the LP gas supplier.
LP Gas Pipe Capacity Table (CU.FT./HR.)
Maximum capacity of pipe in thousands of Btu per hour of undiluted liquified petroleum gasses (at 11 inches water column inlet
pressure). _Based on a Pressure Drop of 0.5 Inch Water Column).
Nominal Length of Pipe in Feet
Iron Pipe
Size,Inches 10 20 30 40 50 60 70 80 90 100 125 100 1/2" 275 189 152 129 114 103 96 89 83 78 69 63 3/4" 367 393 315 26/ 23/ 217 196 182 173 162 146 132
1" 1,071 782 590 304 448 409 378 346 322 307 2/5 202
1 1/4" 2,205 1,496 1,212 1,039 913 1 1/2" 3,307 2,299 1,858 1,559 1,417
834 171 724 6/7 630 067 511 1,275 1,181 1,086 1,023 976 866 187
2" 6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496
The Example (LP): Input Btu requirement of unit, 150,000
Equivalent length of pipe, 60 ft. = 3/4"IPS required.
36 G6RA, G6RK Service Manual
7 Nae) Veni e)\F
Do not re-drill the burner orifices. If the orifice size must be changed, use only new orifices.
GAS CONVERSION AND HIGH ALTITUDE DERATE
High Altitude Derate
The nameplate input rating forthe furnaces apply for elevations up to 2,000 feet (610m) above sea level. For elevations over 2,000 feet, reduce the input by 4% for each 1,000 feet above sea level. For example, a furnace applied at an elevation of 5,000 feet should be derated by 20%. See Table 10 describing the correct orifice for derate.
NOTE: The density of air decreases with increasing elevation above sea level. This reduces the quantity of combustion air drawn into the furnace under normal operation and requires the unit to be derated by using smaller gas orifices or lower manifold pressure.
Conversion Conversion of this furnace to utilize LP/propane gas must be made by qualified service personnel, using only factory authorized or approved parts.
Verifying and Adjusting Firing Rate The firing rate must be verified for each installation to prevent over-firing of the furnace.
IMPORTANT NOTE:
The firing rate must not exceed the rate shown on the furnace rating plate. At altitudes above 2,000 feet it must not exceed that on the rating plate less 4% for each 1,000 feet.
EXAMPLE 1
3,890 feet Natural G6RA096()16 #42 Drill
Elevation
Type of gas Furnace model Orifice as shipped
Whatburner orifices are needed?
The required input for 3890 feet is 81,000 Btu/h or 16% less than the sea level rating of 96,000 Btu/h.
See Table 10 for natural gas, find the Furnace Model Number and follow across the table for the elevation 2000-4000 column. From the table, choose a #43 orifice. Install a #43 orifice in every burner and check firing rate per VERIFYING AND ADJUSTING FIRING RATE section. The firing rate in this example must not exceed 81,000 Btu/h.
G6RA&K Typical Left Side Entry
Manifold
MM ii
Automatic Gas Valve Ma manual shut-off)
G6RA&K- Right Side Entry
Shut-Off Valve igaed tae WY
>< Automatic Gas ™ Ee Valve (with manual y
ain hut-off)
Some utilities
above floor
Burner
Assen
A ~-— Dripleg
Manifold
Figure 53. Typical Gas Service Connection
EXAMPLE 2
5,500 feet Propane G6RA096()-16
Elevation
Type of gas
Furnace model
Orifice in Natural to LP Conversion Kit #55 drill
What burner orifices are needed?
The required input for 5500 feet is 73,000 Btu/h or 24% less than the sea level rating of 96,000 Btu/h.
G6RA, G6RK Service Manual 37
Follow the procedure below to determine the firing rate. 6. Relatively small adjustments to the firing rate can be made by adjusting the gas manifold pressure. 1. Shut off all other gas fired appliances. 7. SeeHigh Altitude Derate for advice on gas orifice size for
Start the furnace and allow it to run for at least three minutes.
installations at elevations more than 2,000 feet above sea level.
3. Measure the time (inseconds) required for the gas meter to complete one revolution.
4. Convert the time per revolution to cubic feet of gas per hour using Table 11.
5. Multiply the gas flow rate in cubic feet per hour by the heating value of the gas in Btu per cubic foot to obtain the firing rate in Btu per hour. Example:
a) Time for one revolution of a gas meter with a one cubic foot dial = 40 seconds.
b) From Table 11 read 90 cubic feet per hour of gas.
c) Heating value of the gas (obtained from gas Supplier) = 1040 Btu per _ cubic
d) Firing rate = 1040 x 90 = 93,600 Biuh.
Furnace Rating No. of Plate Input Brners Btuh
The gas valve regulator is set ata nominal value of 3.2" W.C. for use with natural gas. The manifold pressure must be set at 10" W.C. for use with LP/propane gas. To adjust the manifold pressure, remove the regulator cap and turn the adjusting screw clockwise to increase pressure or counterclockwise to reduce pressure. Replace the regulator cap after adjustments are complete. When adjusting the firing rate, do not set the manifold pressure more than 0.3" W.C. above or below these pressures. If pressures outside this range are required to achieve the desired firing rate, change the burner orifices. Elevation
Elevation Elevation Elevation Elevation 0 - 2000 2000-4000 4000-6000 6000-8000 8000-10000
Nat | LP | Nat | LP | Nat | LP | Nat | LP | Nat | LP |
foot.
Furnace Model Number
Table 10. Approximate Orifice Size for Natural and LP Gases
G(*)RKO60C-X 60,000
GAS FLOW RATE (CUBIC FEET PER HOUR)
TIME FOR CUBIC FEET PER REVOLUTION OF TIME FOR ONE REVOLUTION METER ONE REVOLUTION (SECONDS) 1 10 (SECONDS) 80 82 84 86 88 90 92 94
CUBIC FEET PER REVOLUTION OF METER
96 98
Table 11. Gas Flow Rate 38 G6RA, G6RK Service Manual
ACCESSORIES
Figure 54. Gas Valve and Manifold
ACCESSORIES Dual Fuel Kit (Figure 55)
Figure 55. Dual Fuel Kit
This kit, P/N 914762 is used when a fossil fuel furnace is being used with a heat pump.
Natural Gas to Propane Conversion Kits NORDYNE offers natural gas to propane conversion kits in standard P/N 902995 and high altitudes P/N 902996.
Electronic Air Cleaner (Figure 56)
NORDYNE offers an Electronic Air Cleaner for installation on all G6 series furnaces. These units are powered from the furnace's integrated control board.
Figure 56. Electronic Air Cleaner
G6RA, G6RK Service Manual 39
VENT KIT #903196 BLEED TUBE CHART
WHITE
G6RA 072C-16 G6RA 096C-20 G6RA 072N-16 G6RA O96N-20 G6RA 072C-16-H G6RA 096C-20-H
CLEAR
G6RA144C-20 G6RA 144N-20 G6RA 144C-20-H G6RA 144E-20
RED
G6RA 060C-12 G6RA 072C-12 G6RA 096C-16 G6RA 120C-16 G6RA 120C-20 G6RA O60N-12 G6RA 072N-12 G6RA O96N-16 G6RA 120N-16 G6RA 120N-20 G6RA 060C-12-H G6RA 072C-12-H G6RA 096C-16-H G6RA 120C-16-H G6RA 120C-20-H G6RK 060C-12 G6RK 072C-12 G6RK 072C-16 G6RK 096C-12 G6RK 096C-16 G6RK 120C-20 G6RK 060C-12-H G6RK 072C-12-H G6RK 072C-16-H G6RK 096C-12-H G6RK 096C-16-H G6RK 120C-20-H G6RA 072E-12 G6RA O096E-16 G6RA 120E-20
NOTE: For G6RA 045C-08 NO Bleed Tube Used.
40 G6RA, G6RK Service Manual
Typical meters used to service furnaces.
A B C D
. Differential Pressure Gauge . Volt-Ohm Meter
. Gas Pressure Gauge
. Incline Manometer
407A-0298
Specifications and illustrations subject to change
; without notice and without incurring obligations. St. Louis, MO NORDYNE Printed in U.S.A. (12/97)