Goodman GDH8 User manual

CUS
®
•RefertoServiceManualRS6610004forinstallation,operation,andtroubleshootinginformation.
•Allsafetyinformation must be followedasprovided in the ServiceManual.
•RefertotheappropriatePartsCatalog for part number information.
•Modelnumbers listed on page 3.
Copyright©2011,2013GoodmanManufacturingCompany,L.P.
This manual is to be used by qualified, professionally trained HVAC technicians only.
Goodman does not assume any responsibility for property damage or personal injury
due to improper service procedures or services performed by an unqualified
person.
RT6621022r2
March 2013
GDH8 33-3/8" 80% Gas Furnace
80% AFUE, 2-Stage (Convertible),
Multi-Speed, Dedicated Downflow
TECHNICAL MANUTECHNICAL MANU
TECHNICAL MANUTECHNICAL MANU
TECHNICAL MANUALAL
ALAL
AL

PRODUCT IDENTIFICATION
2
The model and manufacturing number are used for positive identification of component parts used in manufacturing.
Pleaseusethese numbers when requesting serviceorparts information.
Installation and repair of this unit
shouldbeperformedONLYbyindi-
viduals meeting the requirements of an "entry level tech-
nician", at a minimum, as specified by the Air-Condition-
ing,Heating,andRefrigerationInstitute(AHRI). Attempting
to install or repair this unit without such background may
result in product damage, personal injury or death.
Goodman will not be responsible
for any injury or property damage
arising from improper service or service procedures. If
you install or perform service on this unit, you assume
responsibility for any personal injury or property damage
which may result. Many jurisdictions require a license to
install or service heating and air conditioning equipment.
WARNING
WARNING HIGH VOLTAGE!
Disconnect ALL power before servicing or installing this unit. Multiple power
sources may be present. Failure to do so may cause property damage, personal
injury or death.
WARNING
WARNING WARNING
WARNING
G D H 8 060 3 A X A A
AIRFLOW DIRECTION
D: Dedicated Downflow
FURNACE
TYPE
H: Two-Stage/
Multi-speed
AFUE:
8: 80
%
BRAND:
G: Goodman®
Brand
A* Revisions
NOMINAL INPUT:
040: 45,000Btuh
060: 70,000Btuh
080: 90,000Btuh
100: 115,000 Btuh
AIRFLOW
CAPABILITY:
3: 1200
4: 1600
5: 2000
ADDITIONAL
FEATURES:
N: NaturalGas
X: LowNO
x
MAJOR
REVISION:
CABINET WIDTH:
A: 14"
B: 171/2"
C: 21"
MINOR
REVISION:
B* Revisions
NOMINAL INPUT:
040: 40,000 Btuh
060: 60,000 Btuh
080: 80,000 Btuh
100: 100,000Btuh

3
PRODUCT IDENTIFICATION
The model and manufacturing number are used for positive identification of component parts used in manufacturing.
Pleaseusethese numbers when requesting serviceorparts information.
GDH80403A*A*
GDH80603A*A*
GDH80804B*A*
GDH81005C*A*
The United States Environmental Protection Agency (“EPA”) has issued various regulations re-
garding the introduction and disposal of refrigerants introduced into this unit. Failure to follow
these regulations may harm the environment and can lead to the imposition of substantial fines.
These regulations may vary by jurisdiction. Should questions arise, contact your local EPA office.
WARNING
WARNING
Do not connect or use any device
thatisnotdesigncertifiedbyGood-
man for use with this unit. Serious
property damage, personal injury, reduced unit perfor-
mance and/or hazardous conditions may result from the
use of such non-approved devices.
WARNING
WARNING To prevent the risk of property
damage, personal injury, or death,
do not store combustible materials or use gasoline or
other flammable liquids or vapors in the vicinity of this
appliance.
WARNING
WARNING
*Modelsareavailablein Natural Gas and low NOx.
GDH80403A*B*
GDH80603A*B*
GDH80804B*B*
GDH81005C*B*

4
PRODUCT DESIGN NFPA 54/ANSI Z223.1 - latest edition. In Canada, the fur-
nacesmustbeventedinaccordance with theNationalStan-
dard of Canada, CAN/CSA B149.1 and CAN/CSA B149.2
-latesteditionsand amendments.
NOTE: Theverticalheightof the Category I ventingsystem
must be at least as great as the horizontal length of the
ventingsystem.
Accessibility Clearances (Minimum)
Unobstructed front clearance of 24" for servicing is rec-
ommended.
SW B
1036 11
* 24" clearance for serviceability recommended.
MINIMUM CLEARANCE TO COMBUSTIBLE MATERIALS - INCHES
** Single Wall Vent (SW) to be used only as a connector.
Refer to the venting tables outlined in the Installation Manual for
additional venting requirements.
Vent
Sides TopRear Front*
Note: Inall cases accessibility clearanceshall take prece-
dence over clearances from the enclosure where accessi-
bility clearances are greater. All dimensions are given in
inches.
HighAltitudeDerate
IMPORTANT NOTE: The furnace as shipped requires no
change to run between 0 - 4500 feet. Do not attempt to
increase the firing rate by changing orifices or increasing
themanifoldpressurebelow4500feet.Thiscancausepoor
combustionandequipment failure.
Highaltitudeinstallationsabove4500feetmayrequireboth
a pressure switch and an orifice change. These changes
are necessary to compensate for the natural reduction in
the density of both the gas fuel and the combustion air at
higheraltitude.
For installations above 4500 feet, please refer to your dis-
tributorforrequired kit(s). Contact thedistributorfor a tabu-
lar listing of appropriate manufacturer’s kits for propane
gasand/orhighaltitudeinstallations. The indicatedkitsmust
be used to insure safe and proper furnace operation. All
conversions must be performed by a qualified installer, or
service agency.
GeneralOperation
TheGDH8furnacesareequippedwithanelectronicignition
deviceusedtolighttheburnersandaninduceddraftblower
to exhaust combustion products.
An interlock switch prevents furnace operation if the inner
blowerdoor is not inplace. Keep the blower access door in
placeexceptfor inspection and maintenance.(Seeillustra-
tionon page 5.)
This furnace is also equipped with a self-diagnosing elec-
tronic control module. In the event a furnace component is
notoperatingproperly,thecontrolmoduleLED will flashon
and off in a factory-programmed sequence, depending on
theproblemencountered. This light canbeviewed through
theobservationwindowin the blower access door.Referto
theTroubleshootingChartforfurtherexplanationoftheLED
codesandAbnormalOperation-IntegratedIgnitionControl
section in the Service Instructions for an explanation of the
possibleproblem.
Theratedheatingcapacityof the furnace should be greater
thanor equal to thetotal heat lossof the area tobe heated.
The total heat loss should be calculated by an approved
methodorinaccordance with “ASHRAE Guide” or “Manual
J-LoadCalculations”publishedbytheAirConditioning Con-
tractors of America.
*Obtain from: American National Standards Institute 1430
BroadwayNewYork,NY10018
LocationConsiderations
• The furnace should be as centralized as is practical
with respect to the air distribution system.
• Donotinstallthefurnacedirectly on carpeting, tile, or
combustiblematerialotherthanwood flooring.
• When installed in a residential garage, the furnace
mustbepositionedsotheburnersandignition source
are located not less than 18 inches (457 mm) above
the floor and protected from physical damage by ve-
hicles.
Notes:
WARNING
TO PREVENT POSSIBLE PERSONAL INJURY OR DEATH DUE TO ASPHYXIATION,
THIS FURNACE MUST BE CATEGORY IVENTED. DO NOT VENT USING
CATEGORY III VENTING.
CategoryI Venting is ventingat a non-positive pressure. A
furnace vented as Category I is considered a fan-assisted
appliance and the vent system does not have to be “gas
tight.” NOTE: Singlestagegasfurnaceswithinduced draft
blowers draw products of combustion through a heat ex-
changerallowing,in some instances, common venting with
naturaldraftappliances(i.e.waterheaters).All installations
mustbeventedinaccordancewithNationalFuelGasCode

5
PRODUCT DIMENSIONS GDH8
33-3/8”
A
B
28”
High Voltage
Electrical
Low Voltage
Electrical
Gas Inlet
MODEL A B NON-COMBUSTIBLE
FLOOR BASE
GDH80403A***
GDH80603A*** 14 12 1/2 SBT14
GDH80804B*** 17 1/2 16 SBT17
GDH81005C*** 21 19 1/2 SBT21
All dimensions are in inches.

6
PRODUCT DESIGN
*Negative pressure readings are in inches of water column (in *w.c.)
MODEL PART
NO. OPENS*
GDH80403A*A* B1370142 -0.60
GDH80603A*A* B1370158 -0.70
GDH80804B*A* B1370142 -0.60
GDH81005C*A* B1370158 -0.70
PRESSURE SWITCH
Part Number 0130F00035 0130F00036
Open Setting (°F) 220 180
GDH80403A*A* 1---
GDH80603A*A* 1---
GDH80804B*A* --- 1
GDH81005C*A* --- 1
PRIMARY LIMIT
Part Number 10123529
Open Setting (°F) 300
GDH80403A*** 1
GDH80603A*** 1
GDH80804B*** 1
GDH81005C*** 1
ROLLOUT LIMIT SWITCHES
Part Number 0130F00038
Open Setting (°F) 120
GDH80403A*** 1
GDH80603A*** 1
GDH80804B*** 1
GDH81005C*** 1
AUXILIARY LIMIT SWITCHES
GDH8***A*

7
PRODUCT DESIGN
MODEL PART
NO. OPENS*
GDH80403A*B* B1370142 -0.60
GDH80603A*B* B1370142 -0.60
GDH80804B*B* B1370142 -0.60
GDH81005C*B* 0130F00042 -0.80
PRESSURE SWITCH
Part Number 0130F00036 20162901
Open Setting (°F) 180 210
GDH80403A*B* 1 ---
GDH80603A*B* 1 ---
GDH80804B*B* 1 ---
GDH81005C*B* --- 1
PRIMARY LIMIT
*Negative pressure readings are in inches of water column (in *w.c.)
Part Number 10123529
Open Setting (°F) 300
GDH80403A*** 1
GDH80603A*** 1
GDH80804B*** 1
GDH81005C*** 1
ROLLOUT LIMIT SWITCHES
Part Number 0130F00038
Open Setting (°F) 120
GDH80403A*** 1
GDH80603A*** 1
GDH80804B*** 1
GDH81005C*** 1
AUXILIARY LIMIT SWITCHES
GDH8***B*

8
PRODUCT DESIGN
Coil Matches:
Alarge array of Goodman®brandcoilsareavailable for use with theGDH8 furnaces, in dedicateddownflowapplications.
These coils are available in both cased and uncased models (with the option of a field installed TXV expansion device).
These 80% furnaces match up with the existing Goodman®brand coils as shown in the chart below.
Coil Matches (Goodman®units using R22 and R-410A):
• All CAPF coils in B, C, & D widths have insulated blank off plates for use with one size smaller furnaces.
• All CAPF coils have a CAUF equivalent.
• All CHPF coils in B, C & D heights have an insulated Z bracket for use with one size smaller furnace.
• All proper coil combinations are subject to being AHRI rated with a matched outdoor unit.
C A P F 1824 A 6 A
PRODUCT
TYPE:
C: Indoor Coil
CABINET FINISH:
U:Unpainted
P: Painted
N:Unpainted Case
EXPANSION
DEVICE:
F: Flowrate
r
NOMINAL CAPACITY RANGE
@ 13 SEER
1824: 1 1/2 to 2 Tons
3030: 2 1/2 Tons
3636: 3 Tons
3642: 3 to 3 1/2 Tons
3743: 3 to 3 1/2 Tons
4860: 4 & 5 Tons
4961: 4 & 5 Tons
REVISION
A: Revision
NOMINALWIDTH FOR GAS FURNACE
A:Fits 14" Furnace Cabinet
B: Fits 17 1/2" Furnace Cabinet
C: Fits 21" Furnace Cabinet
D: Fits 24 1/2" Furnace Cabinet
N: Does Not Apply (Horizontal SlabCoils)
APPLICATION
A: Upflow/Downflow Coil
H: Horizontal A Coil
S: Horizontal Slab Coil
REFRIGERANT
CHARGE:
6: R-410A or R-22
2: R-22
4: R-410a

9
PRODUCT DESIGN
Thermostats:
NOTE: Complete lineup of thermostats can be found in the Thermostat Specification Sheets.
Filters:
Filters are required with this furnace and must be provided by the installer. The filters used must comply with UL900 or
CAN/ULCS111standards.Installing this furnace without filterswill void the unit warranty
FURNACE INPUT FILTER SIZE
40M 320 in2
60M 483 in2
80M 640 in2
100M 800 in2
DISPOSABLE NOMINAL 300 F.M. FACE VELOCITY
MINIMUM FILTER SIZES for DISPOSABLE FILTERS

10
PRODUCT DESIGN
Dual $aver Configuration & Operation
SECOND
STAGE
ONLY
SECOND
DELAY
SECOND
DELAY
1-STAGE
2-STAGE
HEAT OFF
DELAY
MODE
AUTO
* Switches for White-Rodgers board shown above
With other venders, order of switches may vary
but functionality stays the same.
Dual$aver
This furnace is capable of the following heating modes:
To change from the factor single-stage operation, adjust the
dipswitches on the ignition control as follows:
Note: This furnace is designed to be used
with a single-stage thermostat.
• Modified Two-Stage
> Fixed 5-Min. Low Stage
> Auto Time (1-12 Min.) Low Stage
• Single Stage (Factory Setting)
Start Start
Call for Heat Call for Heat
Safety Circuit Check Safety Circuit Check
Start Furnace
in Low Stage Start Furnace in Low Stage
Low-Heat Blower Low-Heat Blower
DelayTime (5 Min) DelayTime(1-12 Min)
T-Stat Satisfied T-Stat Satisfied
GasValve Switch
to 2nd Stage Gas Valve Switch to 2nd Stage
Blower Switch to
Hi Heat Operation Blower Switch to Hi Heat Operation

FURNACE SPECIFICATIONS
11
NOTES:
* These furnaces are manufactured for natural gas operation. Optional Kits are available for conversion to propane gas operation.
* For elevations above 2000 ft. the rating should be reduced by 4% for each 1000 ft. above sea level. The furnace must not be derated, orifice changes should only
be made if necessary for altitude.
* The total heat loss from the structure as expressed in TOTAL BTU/HR must be calculated by the manufactures method in accordance with the "A.S.H.R.A.E.
GUIDE" or "MANUAL J-LOAD CALCULATIONS" published by the AIR CONDITIONING CONTRACTORS OF AMERICA. The total heat loss calculated should be
equal to or less than the heating capacity. Output based on D.O.E. test procedures, steady state efficiency times output.
Unit specifications are subject to change without notice. ALWAYS refer to the unit's serial plate for the most up-to-date general and electrical information.
1 Natural Gas BTU/h. For altitudes above 2,000’, reduce input rating 4% for each 1,000’ above sea level.
2 DOE AFUE based upon Isolated Combustion System (ICS)
5 Maximum Overcurrent Protection Device refers to maximum recommended fuse or circuit breaker size. May use fuses or HACR-type circuit breakers of the same size as noted.
Notes:
• Allfurnaces are manufacturedfor use on115 VAC,60Hz, single-phaseelectrical supply.
• Gas Service Connection ½” FPT
• Important:Size fuses andwiresproperlyand make electrical connections in accordance withthe National ElectricalCode and/or all existing local codes.
3 Vent and combustion air diameters may vary depending upon vent length.
Refer to the latest editions of the National Fuel Gas Code NFPA 54/ANSI Z223.1 (in the USA) and the Canada National Standard of Canada, CAN/CSA B149.1
and CAN/CSA B142.2 (in Ca
4 Minimum CircuitAmpacity = (1.25 xCirculator Blower Amps)+ID Blower amps. Wiresizeshouldbe determined in accordancewith National ElectricalCodes.
Extensive wire runs will require larger wire sizes.
GDH8***A*
MODEL GDH80403A*A* GDH80603A*** GDH80804B*A* GDH81005C*A*
Btuh Input (US) High Fire(1) 45,000 70,000 90,000 115,000
Output (US) High Fire 36,000 56,000 72,000 92,000
A.F.U.E.(2) 80% 80% 80% 80%
Rated External Static (" w.c.) .20 - .50 .20 - .50 .20 - .50 .20 - .50
Temperature Rise(°F) 35-65 30-60 35-65 40-70
PressureSwitch Trip Point (" w.c.) -0.60 -0.70 -0.60 -0.70
Blower Wheel (D" x W") 10 X6 10 X6 10 X8 10 X10
Blower Horsepower 1/3 1/3 1/2 3/4
Blower Speeds 4444
Available AC @ 0.5” ESP 3 3 4 5
Power Supply 115-60-1 115-60-1 115-60-1 115-60-1
Minimum Circuit Ampacity(MCA)(4) 8.5 8.5 12.9 12.9
Maximum Overcurrent Device(5) 15 15 15 15
Transformer (VA) 40 40 40 40
Heat Anticipator (Amps) 0.7 0.7 0.7 0.7
PrimaryLimitSetting(°F) 220 220 180 180
AuxiliaryLimitSetting(°F) 120 120 120 120
RolloutLimit Setting (°F) 300 300 300 300
Gas Supply Pressure (Natural/Propane) (" w.c.) 7 / 11 7 / 11 7 / 11 7 / 11
Manifold Pressure (Natural/Propane)High Stage("w.c.) 3.5/10 3.5/ 10 3.5/10 3.5/10
OrificeSize(Natural/Propane) #43 /#55 #43/#55 #43/ #55 #43/ #55
Numberof Burners 2345
Vent Connector Diameter (inches) (3) 4444
Shipping Weight (lbs.) 88 92 106 114

FURNACE SPECIFICATIONS
12
NOTES:
* These furnaces are manufactured for natural gas operation. Optional Kits are available for conversion to propane gas operation.
* The total heat loss from the structure as expressed in TOTAL BTU/HR must be calculated by the manufactures method in accordance with the "A.S.H.R.A.E. GUIDE" or "MANUAL
J-LOADCALCULATIONS"publishedbythe AIR CONDITIONING CONTRACTORS OF AMERICA. The total heatlosscalculatedshouldbeequal to or less than the heatingcapacity.
Output based on D.O.E. test procedures, steady state efficiency times output.
Unit specifications are subject to change without notice. ALWAYS refer to the unit's serial plate for the most up-to-date general and electrical information.
1 DOE AFUE based upon Isolated Combustion System (ICS)
4 Maximum Overcurrent Protection Device refers to maximum recommended fuse or circuit breaker size. May use fuses or HACR-type circuit breakers of thesamesize as noted.
Notes:
• All furnaces are manufactured f or use on 115 VAC, 60 Hz, single-phase electrical supply.
• Gas Service Connection ½” FPT
• Important: Size fuses and wires properly and make electrical connections in accordance with the National Electrical Code and/or all existing local codes.
2 Vent and combustion air diameters may vary depending upon vent length.
Refer to the latest editions of the National Fuel Gas Code NFPA 54/ANSI Z223.1 (in the USA) and the Canada National Standard of Canada, CAN/CSA B149.1
and CAN/CSA B142.2 (in Ca
3 Minimum Circuit Ampacity = (1.25 x Circulator Blower Amps) + ID Blower amps. Wire size should be determined in accordance with National Electrical Codes.
Extensive wire runs will require larger wire sizes.
GDH8***B*
MODEL GDH80403A*B* GDH80603A*B* GDH80804B*B* GDH81005C*B*
Btuh Input(US) High Fire 40,000 60,000 80,000 100,000
Output (US) High Fire 32,000 48,000 64,000 80,000
A.F.U.E.(1) 80% 80% 80% 80%
Rated External Static (" w.c.) .20 - .50 .20 - .50 .20 - .50 .20 - .50
Temperature Rise(°F) 25-55 30-60 35-65 40-70
Pressure Switch Trip Point ("w.c.) -0.60 -0.60 -0.60 -0.80
Blower Wheel (D" x W") 10 X 6 10 X6 10 X8 10 X 10
Blower Horsepower 1/3 1/3 1/2 3/4
Blower Speeds 4 4 4 4
Available AC @ 0.5” ESP 3345
Power Supply 115-60-1 115-60-1 115-60-1 115-60-1
Minimum Circuit Ampacity(MCA)(3) 8.5 8.5 12.9 12.9
Maximum OvercurrentDevice(4) 15 15 15 15
Transformer (VA) 40 40 40 40
Heat Anticipator (Amps) 0.7 0.7 0.7 0.7
PrimaryLimitSetting (°F) 180 180 180 210
AuxiliaryLimitSetting (°F) 120 120 120 120
Rollout Limit Setting (°F) 300 300 300 300
Gas SupplyPressure(Natural/Propane)(" w.c.) 7/11 7 / 11 7 / 11 7 /11
Manifold Pressure (Natural/Propane) High Stage (" w.c.) 3.5 / 10 3.5 / 10 3.5 /10 3.5 /10
Orifice Size (Natural/Propane) #45 / #55 #45 / #55 #45 / #55 #45 / #55
Number of Burners 2 3 4 5
Vent Connector Diameter (inches) (2) 4444
Shipping Weight (lbs.) 88 92 106 114

BLOWER PERFORMANCE SPECIFICATIONS
13
NOTES:
• CFM in chart is without filter(s). Filters do not ship with this furnace, but must be provided by the installer.
• All furnaces ship as high-speed cooling. Installer must adjust blower cooling speed as needed.
• For most jobs, about 400 CFM per ton when cooling is desirable
• INSTALLATION IS TO BE ADJUSTED TO OBTAIN TEMPERATURE RISE WITHIN THE RANGE SPECIFIED ON THE RATING PLATE.
• The chart is for information only. For satisfactory operation, external static pressure must not exceed values shown on the rating plate. The shaded area
indicates
ranges in excess of maximum static pressure allowed when heating.
• The dashed (- - -) areas indicate a temperature rise not recommended for this model.
• At higher altitudes, a properly de-rated unit will have approximately the same temperature rise at a
particular CFM, while ESP at the CFM will be lower.
GDH8***A*
Tons AC
at 0.5" 0.6 0.7 0.8
ESP CFM RISE CFM RISE CFM RISE CFM RISE CFM RISE CFM CFM CFM
High 3.0 1,353 25 1,290 26 1,246 27 1,199 28 1,149 29 1,116 1,116 1,099
Med 2.5 1,183 28 1,113 30 1,098 30 1,052 32 1,039 32 1,006 1,012 969
Med-Lo 2.0 980 34 946 35 920 36 900 37 896 37 885 855 804
Low 1.5 778 43 762 44 738 45 746 45 738 45 717 696 678
High 3.0 1,290 40 1,236 42 1,194 43 1,166 44 1,176 44 1,166 1,108 1,029
Med 2.5 1,139 46 1,090 48 1,035 50 1,063 49 1,063 49 1020 962 895
Med-Lo 2.0 962 54 927 56 925 56 941 55 909 57 877 834 779
Low 1.5 787 66 776 67 763 68 744 70 723 72 690 641 581
High 4.0 2,128 31 2,063 32 2,001 33 1,927 35 1,824 37 1,726 1,628 1,529
Med 3.5 1,840 36 1,788 37 1,745 38 1,689 39 1,625 41 1,550 1,470 1,364
Med-Lo 3.0 1,602 42 1,558 43 1,543 43 1,493 45 1,455 46 1,402 1,328 1,239
Low 2.5 1,277 52 1,252 53 1,244 54 1,229 54 1,214 55 1,179 1141 1079
High 5.0 2,405 35 2,361 36 2,250 38 2,161 39 2,037 42 1,937 1,808 1,689
Med 4.0 1,880 45 1,838 46 1,794 47 1,734 49 1,677 51 1,568 1,510 1,401
Med-Lo 3.5 1659 51 1,630 52 1,587 54 1,537 55 1,492 57 1,445 1,368 1,287
Low 3.0 1,472 58 1,454 59 1,404 61 1,366 62 1,326 64 1300 1228 1139
BLOWER PERFORMANCE
0.1 0.2 0.3 0.4 0.5
(CFM & TemperatureRisevs. External Static Pressure)
Model Motor
Speed
EXTERNAL STATIC PRESSURE (Inches Water Column)
GDH8
0403A*A*
GDH8
0603A*A*
GDH8
0804B*A*
GDH8
1005C*A*

BLOWER PERFORMANCE SPECIFICATIONS
14
GDH8***B*
NOTES:
• CFM in chart is without filter(s). Filters do not ship with this furnace, but must be provided by the installer.
• All furnaces ship as high-speed cooling. Installer must adjust blower cooling speed as needed.
• For most jobs, about 400 CFM per ton when cooling is desirable
• INSTALLATION IS TO BE ADJUSTED TO OBTAIN TEMPERATURE RISE WITHIN THE RANGE SPECIFIED ON THE RATING PLATE.
• The chart is for information only. For satisfactory operation, external static pressure must not exceed values shown on the rating plate. The shaded area
indicates
ranges in excess of maximum static pressure allowed when heating.
• The dashed (- - -) areas indicate a temperature rise not recommended for this model.
• At higher altitudes, a properly de-rated unit will have approximately the same temperature rise at a
particular CFM, while ESP at the CFM will be lower.
Tons AC
at 0.5" 0.6 0.7 0.8
ESP CFM RISE CFM RISE CFM RISE CFM RISE CFM RISE CFM CFM CFM
High 3.0 1,353 ---- 1,290 ---- 1,246 ---- 1,199 25 1,149 26 1,116 1,116 1,099
Med 2.5 1,183 25 1,113 27 1,098 27 1,052 28 1,039 29 1,006 1,012 969
Med-Lo 2.0 980 30 946 31 920 32 900 33 896 33 885 855 804
Low 1.5 778 38 762 39 738 40 746 40 738 40 717 696 678
High 3.0 1,290 34 1,236 36 1,194 37 1,166 38 1,176 38 1,166 1,108 1,029
Med 2.5 1,139 39 1,090 41 1,035 43 1,063 42 1,063 42 1,020 962 895
Med-Lo 2.0 962 46 927 48 925 48 941 47 909 49 877 834 779
Low 1.5 787 56 776 57 763 58 744 60 723 ---- 690 641 581
High 4.0 2,128 ---- 2,063 ---- 2,001 ---- 1,927 ---- 1,824 ---- 1,726 1,628 1,529
Med 3.5 1,840 ---- 1,788 ---- 1,745 ---- 1,689 35 1,625 36 1,550 1,470 1,364
Med-Lo 3.0 1,602 37 1,558 38 1,543 38 1,493 40 1,455 41 1,402 1,328 1,239
Low 2.5 1,277 46 1,252 47 1,244 48 1,229 48 1,214 49 1,179 1,141 1,079
High 5.0 2,405 ---- 2,361 ---- 2,250 ---- 2,161 ----- 2,037 36 1,937 1,808 1,689
Med 4.0 1,880 39 1,838 40 1,794 41 1,734 43 1,677 44 1,568 1,510 1,401
Med-Lo 3.5 1,659 45 1,630 45 1,587 47 1,537 48 1,492 50 1,445 1,368 1,287
Low 3.0 1,472 50 1,454 51 1,404 53 1,366 54 1,326 56 1,300 1,228 1,139
GDH8
0403A*B*
GDH8
0603A*B*
GDH8
0804B*B*
GDH8
1005C*B*
BLOWER PERFORMANCE
0.1 0.2 0.3 0.4 0.5
(CFM & Temperature Risevs. External Static Pressure)
Model Motor
Speed
EXTERNAL STATIC PRESSURE (Inches Water Column)

BLOWER PERFORMANCE SPECIFICATIONS
15
30 40 50 60 70 80 90 110 120
100 130 140 150
100
90 80
70 60 50
40 30 20
10
OUTPUT BTU/HR x 1000
BTU OUTPUT vs TEMPERATURE RISE CHART
TEMPE
R
ATU
R
E
R
ISE
600 CFM
700
900
1000
1100
1200
1400
1600
1800
2000
2200
2400 CFM
FORMULAS
BTU OUTPUT = CFM x 1.08 x RISE
RISE = BTU OUTPUT
1.08 ÷ CFM
800

16
WIRING DIAGRAM
HIGH VOLTAGE! DISCONNECT ALL POWER BEFORE SERVICING OR INSTALLING THIS UNIT. MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
Wiring is subject to change. Always refer to the wiring diagram on the unit for the most up-to-date wiring.
GDH8
CAP
BK(HI)
AUXILIARY
PROPERLYPOLARIZEDANDGROUNDED.
SERVICING.WIRINGTOUNITMUSTBE
WARNING:DISCONNECTPOWERBEFORE
XFMR
BK
115V
24V
BR
LIMITS
WH(N)
RD(LOW)
OR(MEDLOW)
BL(MED)
BLOWER
CICULATOR
24VTHERMOSTATCONNECTIONS
RO2(11) LIMIT
GND(8)
HUMIDIFIER
XFMR(6) GND
G
C
W
YTO
MICRO
R
MVL(2)
MVC(9)
AUXILIARY
LIMITCONTROLS
PS(10)
PSO(4)
HLI(7)
HLO(1)
CONTROLMODULE
INTEGRATED
NO
SWITCH
PRESSURE
IDBLOWER
VALVE
M1
GAS
C2
C
AUTORESET
PRIMARY
MANUALRESETROLLOUT
LIMITCONTROL(S)
115VAC
FLAMESENSOR
FP
XFMR-H
XFMR(3)
RO1(5)
24VAC
HOTSURFACE
IGNITER
INTEGRATEDCONTROLMODULE
BR
BR
COOL-H
IGN
IND
ID
BLWR
CIRCULATOR
HEAT-H
BLWR
TRANSFORMER
40VA
CONTROL
XFMR-N
INTEGRATEDCONTROLMODULE
CIR-N
0140F00662 REV.A
5.UNITMUSTBEPERMANENTLYGROUNDEDANDCONFORMTON.E.C.ANDLOCALCODES.
ONSOMEMODELS
HUMIDIFIER
24VAC
INDUCEDDRAFT
°C.USECOPPERCONDUCTORSONLY.
BLOWERCOMPARTMENT
BURNERCOMPARTMENT
REPLACED,ITMUSTBEREPLACEDWITHWIRINGMATERIALHAVINGATEMPERATURE
3.IFANYOFTHEORIGINALWIREASSUPPLIEDWITHTHEFURNACEMUSTBE
CORRECTCOOLINGCFM.(SEESPECSHEETFORAIRFLOWCHART)
REQUIREMENTSSOASTOPROVIDETHECORRECTHEATINGTEMPERATURERISEANDTHE
4.BLOWERSPEEDSSHOULDBEADJUSTEDBYINSTALLERTOMATCHTHEINSTALLATION
INTEGRATEDCONTROL
INTERNALTO
2.MANUFACTURER'SSPECIFIEDREPLACEMENTPARTSMUSTBEUSEDWHENSERVICING.
1.SETHEATANTICIPATORONROOMTHERMOSTATAT0.7AMPS.
BLOWER
PRIMARYLIMIT
WH
GR
BK
IGNITER
SURFACE
HOT
PU
RD
15PINPLUG
C
NO
SWITCH
PRESSURE
BR
SENSOR
FLAME
BK
WH
ROLLOUTLIMITS
RAPIDFLASHES=REVERSED115VACPOLARITY/VERIFYGND
SYSTEMLOCKOUT(RETRIES/RECYCLESEXCEEDED)
7FLASHES=LOWFLAMESIGNAL
5FLASHES=FLAMESENSEWITHOUTGASVALVE
4FLASHES=OPENHIGHLIMIT
3FLASHES=PRESSURESWITCHSTUCKOPEN
2FLASHES=PRESSURESWITCHSTUCKCLOSED
STEADYON=NORMALOPERATION
OFF =CONTROLFAILURE
5
1FLASH =
0
1
2
3
4
PU
6FLASHES=OPENROLLOUTOROPENFUSE
COLORCODES:
PUPURPLE
OR ORANGE
YLYELLOW
6
7
8
BKBLACK
GRGREEN
BRBROWN
PKPINK
RD RED
GYGRAY
BLBLUE
WH WHITE
PU
RATINGOFATLEAST105
NOTES:
OVERCURRENTPROTECTIONDEVICE
JUNCTIONBOX
MUSTBE
WARNING:
SWITCH
WIRINGTOUNIT
BEFORESERVICING.
DISCONNECTPOWER
LINE-H
DOOR
ANDGROUNDED.
POLARIZED
PROPERLY
LGND
LINE-N
DISCONNECT
N
SWITCH(TEMP.)
FIELDSPLICE
SWITCH(PRESS.)
PROT.DEVICE
OVERCURRENT
EQUIPMENTGND
TERMINAL
JUNCTION
HIVOLTAGEFIELD
HIVOLTAGE(115V)
LOWVOLTAGEFIELD
LOWVOLTAGE(24V)
PLUGCONNECTION
IGNITER
FIELDGND
IND-N
IGN-N
JUNCTION
BOX
OVERCURRENTPROTECTION
POWERSUPPLYWITH
TO115VAC/1/60HZ
GND
LINE-N
LINEH
DEVICE
DOORSWITCH
WH
BK
SWITCHLOCATEDINBLOWER
COMPARTMENTONSOMEMODELS
RD
RD
BL
PU
YL
OR
BR
(SINGLECONTROLONSOMEMODELS)
(SINGLECONTROLONSOMEMODELS)
DIAGNOSTIC
LED LOHEAT-H
PARK
SEENOTE6
COOL-HHIHEAT-H
978
654
12
CGRWY
5MIN
2STG
100SEC
1STG
AUTO
150SEC MODE
2NDSTGDLY
HTOFFDLY
2
1
EAC-HLINE-HXFMR-H
LINENEUTRAL
FS
1110
321
CONTROLMODULE
INTEGRATED
FUSE
PM
1HIC23
2STAGE
GASVALVE
(HONEYWELL)
WH
24VAC
HUMIDIFIER
RD
HI
MVH(12)
HI
LO
HEAT-H
AIRCLEANER
ELECTRONIC EAC-N
EAC-H
6.TORECALLTHELAST5FAULTS,MOSTRECENTTOLEASTRECENT,DEPRESSSWITCH
FORMORETHAN2SECONDSWHILEINSTANDBY(NOTHERMOSTATINPUTS).
WH BL
BR
WH
BL
BK
BK
YL
YL
RD
YL YL
PU
OR
WH
WH
WH
WH
YL
BL
RD
C
8FLASHES=CHECKIGNITERORIMPROPERGROUND

17
SCHEMATICS
HIGH VOLTAGE!
DISCONNECT ALL POWER BEFORE SERVICING OR INSTALLING THIS
UNIT. MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO
DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
TYPICALSCHEMATIC
GDH8____X*MODEL FURNACES
WR50M56-289INTEGRATEDIGNITIONCONTROL
Thisschematic is for referenceonly. Not all wiringis as shown above.Refer to the appropriatewiring diagram for theunit being serviced.
.0005
3M K4
K2
HI
HEAT
COOL PARK CIR
NEU
K5
GAS VALVE
HIGH LIMIT AUX
LIMIT
PRESSURE SWITCH
FLAME
SENSOR PROBE
IGNITOR
FP IGN GND MV MLV PS HLO HLI
CIRCULATOR
BLOWER
XFMR HOT
XFMR NEU
24 VAC
TH
RO1 RO2
R
TR C
Y
G
W
COMPRESSOR CONTACTOR COIL
THERMOSTAT
R
Y
G W
INDUCER
IND
ELECTRONIC
AIR CLEANER
EAC EAC
NEU
K6 ROLLOUT
SWITCH
K1
FACTORY JUMPER
FACTORY JUMPER
PSO
K2
K3
K3
LO
HEAT
COM
PM
HI
2-STAGE
K7
Wiring is subject to change. Always refer to the wiring diagram on the unit for the most up-to-date wiring.