Goodman Amana GMH8 User manual

RT6621024r4
November2013
Copyright©2011,2013GoodmanManufacturingCompany,L.P.
This manual is to be used by qualified, professionally trained HVAC technicians only.
Goodmandoesnotassumeanyresponsibilityforpropertydamageorpersonalinjury
duetoimproperserviceproceduresorservices performed by an unqualifiedperson.
•RefertoServiceManual RS6612007fortroubleshootinginformation.
•Allsafety information must befollowed as provided inthe Service Manual.
•RefertotheappropriateParts Catalog for part number information.
•Model numbers listed on page 3.
GMH8 33-3/8" 80% Gas Furnace
80%AFUE,2-Stage(Convertible),
Multi-Speed,Upflow/Horizontal
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.
Please use these numbers when requesting service or parts information.
WARNING
WARNING HIGHVOLTAGE!
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.
Installation and repair of this unit
should be performed ONLY by
individuals meeting the requirements of an "entry level
technician" (at a minimum), as specified by the Air-
Conditioning,Heating,andRefrigeration Institute(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 juris-
dictions require a license to install or service heating and
air conditioning equipment.
WARNING
WARNING WARNING
WARNING
GMH8 040 3AXAA
SUPPLY TYPE:
M: Upflow/Horizontal
FURNACE TYPE:
H: Twin ComfortTM
Multi-Speed
AFUE:
8: 80%
PRODUCT
TYPE:
G: Goodman®
Brand
AIRFLOW
CAPABILITY:
3: 1200
4: 1600
5: 2000
CABINET WIDTH:
A:14" C: 21"
B: 17 1/2" D: 24 1/2"
ADDITIONAL
FEATURES:
N: Natural Gas
X: Low NOx
MAJOR REVISION:
A: Initial Release
MINOR REVISION:
A: Initial Release
NOMINAL CAPACITY
040: 40,000 BTUH
060: 60,000 BTUH
080: 80,000 BTUH
100: 100,000 BTUH
120: 120,000 BTUH
140: 140,000 BTUH

PRODUCT IDENTIFICATION
3
The model and manufacturing number are used for positive identification of component parts used in manufacturing.
Please use these numbers when requesting service or parts information.
* Models available with Natural Gas and low NOx .
The United States Environmental Protection Agency (“EPA”) has issued various regulations regard-
ing 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
that is not design certified by
Goodman for use with this unit.
Serious property damage, personal injury, reduced unit
performance 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
GMH80403A*BB
GMH80603A*BB
GMH80604B*BB
GMH80803B*BB
GMH80804B*BB
GMH80805C*BB
GMH81005C*BB
GMH81205D*BA
GMH81405DNCC

4
PRODUCT DESIGN
WARNING
TO PREVENT POSSIBLE PERSONAL INJURY OR DEATH DUE TO ASPHYXIATION,
THIS FURNACE MUST BE CATEGORY IVENTED. DO NOT VENT USING
CATEGORY III VENTING.
1. Category I Venting is venting at a non-positive pres-
sure. A furnace vented as Category I is considered a
fan-assisted appliance and the vent system does not
have to be “gas tight.” NOTE: Single stage gas fur-
naceswithinduceddraftblowersdrawproductsof com-
bustion through a heat exchanger allowing, in some in-
stances, common venting with natural draft appliances
(i.e. water heaters). All installations must be vented in
accordancewith NationalFuelGasCode NFPA54/ANSI
Z223.1 - latest edition. In Canada, the furnaces must
be vented in accordance with the National Standard of
Canada,CAN/CSA B149.1 and CAN/CSAB149.2 - lat-
esteditionsandamendments.
NOTE: Theverticalheight of the Category Iventing system
must be at least as great as the horizontal length of the
ventingsystem.
2. Line voltage wiring can enter through the right or left
sideofthe furnace. Lowvoltagewiringcanenterthrough
the right or left side of furnace.
3. Conversion kits for propane gasand high altitude natu-
ral and propane gas operation are available. See High
Altitude Derate chart for details.
4. Installer must supply the following gas line fittings, de-
pending on which entrance is used:
Left -- Two 90° Elbows, one close nipple, straight pipe
Right -- Straight pipe to reach gas valve.
General Operation
The GMH8 furnaces are equipped with an electronic igni-
tion device used to light the burners and an induced draft
blowertoexhaustcombustion products.
Aninterlockswitch prevents furnace operation ifthe blower
door is not in place. Keep the blower access door in place
except for inspection and maintenance.
This furnace is also equipped with a self-diagnosing elec-
tronic control module. In the event a furnace component is
not operating properly, the control module LED will flash
on and off in a factory-programmed sequence, depending
ontheproblemencountered.Thislightcanbeviewedthrough
theobservationwindow in the blower accessdoor. Refer to
the Troubleshooting Chart for further explanation of the
LED codes and Abnormal Operation - Integrated Ignition
Control section in the Service Instructions for an explana-
tionof thepossible problem.
Theratedheatingcapacity of the furnace shouldbegreater
thanor equal tothe total heatloss of thearea to beheated.
The total heat loss should be calculated by an approved
methodorin accordance with “ASHRAE Guide”or“Manual
J-LoadCalculations”publishedbythe Air Conditioning Con-
tractors of America.
*Obtain from: American National Standards Institute 1430
Broadway New York, NY 10018
LocationConsiderations
• The furnace should be as centralized as is practical
with respect to the air distribution system.
• Do not install the furnace directly on carpeting, tile,
orcombustible material other than wood flooring.
• When suspending the furnace from rafters or joists,
use 3/8" threaded rod and 2” x 2” x 3/8” angle as
showninthe InstallationandServiceInstructions.The
length of the rod will depend on the application and
clearance necessary.
• When installed in a residential garage, the furnace
mustbepositionedsotheburners and ignition source
are located not less than 18 inches (457 mm) above
the floor and protected from physical damage by ve-
hicles.

5
PRODUCT DESIGN
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 conncetor.
Refer to the venting tables outlined in the Installation Manual for
additional venting requirements.
Vent
Sides TopRear Front*
Note: In all cases accessibility clearance shall take pre-
cedence over clearances from the enclosure where ac-
cessibilityclearancesaregreater. Alldimensionsaregiven
in inches.
HighAltitudeDerate
IMPORTANT NOTE: The furnace as shipped requires no
change to run between 0 - 5500 feet. Do not attempt to
increase the firing rate by changing orifices or increasing
themanifoldpressurebelow5500feet.Thiscancausepoor
combustionandequipmentfailure.
Highaltitudeinstallationsabove5500feetmay require both
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 5500 feet, please refer to your dis-
tributorforrequired kit(s). Contactthedistributor for a tabu-
larlistingofappropriatemanufacturer’skitsforpropanegas
and/orhighaltitudeinstallations. The indicated kits mustbe
usedtoinsuresafeandproperfurnaceoperation.Allconver-
sions must be performed by a qualified installer, or service
agency.

COMPONENT IDENTIFICATION
6
躀
Pressure Switch
Tubular Heat Exchanger
Flue Pipe Connection
Gas Line Entrance
(Alternate)
Induced Draft Blower
(Chimney Transition Top Shipped Loose)
Gas Line
Entrance
Gas Valve
Rollout Limit
Junction Box
Wiring Harness
Grommet
Gas Manifold
Inshot Burner
Blower Door
Interlock Switch
Integrated Control Module
Transformer Circulator Blower
1
2
3
4
5
6
78
9
1 TubularHeatExchanger
2 PressureSwitch
3 Flue Pipe Connection
4 Induced Draft Blower
5 Gas Line Entrance
6 GasValve
7 RolloutLimit
8 JunctionBox
9 WiringHarness Grommet
10 GasManifold
11 Inshot Burner
12 Transformer
13 IntegratedControlModule
14 Blower Door Interlock Switch
15 Circulator Blower
16 Gas Line Entrance(Alternate)

PRODUCT DIMENSIONS
7
GMH8
A
lt. Gas Inlet
High Voltage Inlet
Low Voltage
A
lt. Gas Inlet
A
lt. High Voltage
Alt. LowVoltage
UNITS A B
GMH80403A***
GMH80603A*** 14 12.5
GMH80604B***
GMH80803B***
GMH80804B*** 17.5 16
GMH80805C***
GMH81005C*** 21 19.5
GMH81205D*** 24.5 23
GMH81405DNC* 24.5 23
All dimensions are in inches.

8
PRODUCT DESIGN
For installaions in Canada, the GMH8 furnace is certified only to 4,500 ft.
* Negative pressure readings are in inches of water column (*w.c.)
GMH8***BB
GMH81405DNCC
MODEL
TRIP POINT
ID BLOWER
PRESSURE
SWITCH
IDBLOWER
PRESSURE
SWITCH
PART #
GMH80403A*BB -0.70 B1370158
GMH80603A*BB -0.75 B1370179
GMH80604B*BB -0.75 B1370179
GMH80803B*BB -0.70 B1370158
GMH80804B*BB -0.70 B1370158
GMH80805C*BB -0.75 B1370179
GMH81005C*BB -0.70 B1370158
GMH81205D*BA -0.80 0130F00042
GMH81405DNCC -0.80 0130F00042
PRESSURESWITCH TRIP POINTS
AND USAGE CHART
Part Number 20162904 20162903 20162901
Open Setting (°F) 150 160 210
GMH80403A*BB --- --- 1
GMH80603A*BB 1 --- ---
GMH80604B*BB 1 --- ---
GMH80803B*BB 1 --- ---
GMH80804B*BB 1 --- ---
GMH80805C*BB --- 1 ---
GMH81005C*BB 1 --- ---
GMH81205D*BA --- 1 ---
GMH81405DNCC --- 1 ---
PRIMARY LIMIT
Part Number 10123529
Open Setting (°F) 300
GMH80403A*** 2
GMH80603A*** 2
GMH80604B*** 2
GMH80803B*** 2
GMH80804B*** 2
GMH80805C*** 2
GMH81005C*** 2
GMH81205D*** 2
GMH81405DNCC 2
ROLLOUT LIMIT SWITCHES
Part Number 0130F00038
Open Setting (°F) 120
GMH80403A*** 1
GMH80603A*** 1
GMH80604B*** 1
GMH80803B*** 1
GMH80804B*** 1
GMH80805C*** 1
GMH81005C*** 1
GMH81205D*** 1
GMH81405DNCC 1
AUXILIARY LIMIT SWITCHES

9
PRODUCT DESIGN
Coil Matches:
Alarge array of Goodman® brand coils are availablefor use with theGDH8 furnaces, in dedicateddownflow applications.
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: Flowrater
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: DoesNotApply (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

10
PRODUCT DESIGN
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 filters willvoid the unitwarranty.
This furnace has provisions for the installation of return air filters at the side and/or bottom return. The furnace will
accommodate the following filter sizes depending on cabinet size:
Referto MinimumFilter Areatables todetermine filterarea requirement.NOTE: Filters can also be installed elsewhere
in the duct system such as a central return.
Upflow Filters
Cabinet
Width
(in.)
Nominal
Filter Size
(in.)
Approx.
Flow Area
(in2)
Cabinet
Width
(in.)
Nominal
Filter Size
(in.)
Approx.
Flow Area
(in2)
All 16 x 25 x 1 400 14 12 x 25 x 1 300
17-1/2 14 x 25 x 1 350
21 16 x 25 x 1 400
24-1/2 20 x 25 x 1 500
Side Return(s) Bottom Return
Thermostats:
It is recommended that a single-stage heat , non-power robbing thermostat be used. Refer to the product marketing
literature for a complete list of thermostats offered.
FURNACE INPUT FILTER SIZE
40M 320in2
60M 483in2
80M 640in2
100M 800 in2
120M 738 in2
140M 738 in2
DISPOSABLE NOMINAL300 F.M. FACE VELOCITY
MINIMUM FILTER SIZES for DISPOSABLE FILTERS

11
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
12
NOTES:
1. The total heat loss from the structure as expressed in TOTAL BTU/HR must be calculated by the manufacturers method or in accordance with the
"A.S.H.R.A.E.GUIDE"or"MANUALJ-LOADCALCULATIONS"publishedbytheAIRCONDITIONINGCONTRACTORSOFAMERICA.Thetotal
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.
* LowNOxmodelavailable
1. Thesefurnacesaremanufactured for natural gas operation.Optionalkitsareavailableforconversiontopropane operation.
2. MinimumCircuitAmpacitycalculatedas:(1.25 x Circulator Blower Amps) + I.D. Blower Amps. Wire sizes should be determined in accordance with
NationalElectricalCodes.Extensivewirerunswillrequirelargerwiresizes.
3 Maximum Overcurrent protections Device refers to maximumrecommended fuse or circult breaker size. May use time delay fuses or HACR-type
circuit breakers of the same sizes as noted.
GMH8***BB
MODEL
GMH80403A*BB GMH80603A*BB GMH80604B*BB GMH80803B*BB GMH80804B*BB
Input, Natural Gas (BTUH) 40,000 60,000 60,000 80,000 80,000
Output, Natural Gas (BTUH) 132,000 48,000 48,000 64,000 64,000
Output, LP (BTUH) 32,000 48,000 48,000 64,000 64,000
A.F.U.E. 80.0% 80.0% 80.0% 80.0% 80.0%
Rated External Static (" w.c.) 0.20 - 0.50 0.20 - 0.50 0.20 - 0.50 0.20 - 0.50 0.20 - 0.50
Temperature Rise (°F) 25 - 55 20 - 50 20 - 50 35 - 65 35 - 65
Pressure Switch Trip Point (" w.c.) -0.70 -0.75 -0.75 -0.70 -0.70
Blower Wheel (D" x W") 10x6 10x6 10x8 10x8 10x8
Blower Horsepower 1/3 1/3 1/2 1/3 1/2
Blower Speeds 4 4 4 4 4
Max CFM@ 0.5 E.S.P. 1298 1157 1883 1448 1725
Power Supply (Volts/Hz/Ph) 115/60/1 115/60/1 115/60/1 115/60/1 115/60/1
Minimum Circuit Ampacity (MCA) 28.1 8.1 12.5 8.1 12.5
Maximum Overcurrent Device 315 15 15 15 15
Transformer (VA) 40 40 40 40 40
Primary Limit Setting (°F) 210 150 150 150 150
Auxiliary Limit Setting (°F) 120 120 120 120 120
Rollout Limit Setting (°F) 300 300 300 300 300
Fan Delay On Heating 30 30 30 30 30
Off Heating * 150 150 150 150 150
FanDelayOnCooling 66666
Off Cooling 45 45 45 45 45
FanDelayOn-FanOnly 00000
Gas Supply Pressure
(Natural/Propane) (" w.c.) 7 / 11 7 / 11 7 / 11 7 / 11 7 / 11
Manifold Pressure
(Natural/Propane) (" w.c.) 3.5 / 10 3.5 / 10 3.5 / 10 3.5 / 10 3.5 / 10
Orifice Size (Natural/Propane) 45 / 55 45 / 55 45 / 55 45 / 55 45 / 55
NumberofBurners 23344
Vent Connector Diameter (inches) 4 4 4 4 4
Shipping Weight (lbs.) 86 90 98 106 107

FURNACE SPECIFICATIONS
13
NOTES:
1. For elevations above 2000 feet the rating should be reduced by 4% for each 1000 feet above sea level. The furnace must not be derated, orifice
changes should only be made if necessary for altitude.
2. The total heat loss from the structure as expressed in TOTAL BTU/HR must be calculated by the manufacturers method or in accordance with the
"A.S.H.R.A.E.GUIDE"or"MANUALJ-LOADCALCULATIONS"publishedbytheAIRCONDITIONINGCONTRACTORSOFAMERICA.Thetotal
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.
* LowNOxmodelavailable
1. Thesefurnacesaremanufactured for natural gas operation.Optionalkitsareavailableforconversiontopropane operation.
2. MinimumCircuitAmpacitycalculatedas:(1.25 x Circulator Blower Amps) + I.D. Blower Amps. Wire sizes should be determined in accordance with
NationalElectricalCodes.Extensivewirerunswillrequirelargerwiresizes.
3 Maximum Overcurrent protections Device refers to maximumrecommended fuse or circult breaker size. May use time delay fuses or HACR-type
circuit breakers of the same sizes as noted.
MODEL
GMH80805C*BB GMH81005C*BB GMH81205D*BA
GMH81405DNCC
Input, Natural Gas (BTUH) 80,000 100,000 120,000 140,000
Output, Natural Gas (BTUH) 164,000 80,000 96,000 112,000
Output, LP (BTUH) 64,000 80,000 96,000 96,000
A.F.U.E. 80.0% 80.0% 80.0% 80.0%
Rated External Static (" w.c.) 0.20 - 0.50 0.20 - 0.50 0.20 - 0.50 0.20 - 0.50
Temperature Rise (°F) 35 - 65 35 - 65 40 - 70 40 - 70
Pressure Switch Trip Point (" w.c.) -0.75 -0.70 -0.80 -0.80
Blower Wheel (D" x W") 10x10 10x10 11X10 11X10
Blower Horsepower 1/2 1/2 3/4 3/4
Blower Speeds 4 4 4 4
Max CFM@ 0.5 E.S.P. 1960 1974 2131 2131
Power Supply (Volts/Hz/Ph) 115/60/1 115/60/1 115/60/1 115/60/1
Minimum Circuit Ampacity (MCA) 212.5 12.5 14.7 14.7
Maximum Overcurrent Device 315 15 15 15
Transformer (VA) 40 40 40 40
Primary Limit Setting (°F) 160 150 160 160
Auxiliary Limit Setting (°F) 120 120 120 120
Rollout Limit Setting (°F) 300 300 300 300
Fan Delay On Heating 30 30 30 30
Off Heating * 150 150 150 150
Fan Delay On Cooling 6 6 6 6
Off Cooling 45 45 45 45
Fan Delay On - Fan Only 0 0 0 0
Gas SupplyPressure
(Natural/Propane) (" w.c.) 7 / 11 7 / 11 7 / 11 7 / 11
Manifold Pressure
(Natural/Propane) (" w.c.) 3.5 / 10 3.5 / 10 3.5 / 10 3.5 / 10
Orifice Size (Natural/Propane) 45 / 55 45 / 55 45 / 55 43 / 55
Number of Burners 4 5 6 6
Vent Connector Diameter (inches) 4 4 4 4
Shipping Weight (lbs.) 114 118 132 132
GMH8***BB
GMM81405DNCC

BLOWER PERFORMANCE SPECIFICATIONS
14
1. CFM in chart is without filters(s). Filters do not ship with this furnace, but must be provided by the installer.
2. All furnaces ship as high speed cooling. Installer must adjust blower cooling speed as needed.
3. For most jobs, about 400 CFM per ton when cooling is desirable.
4. INSTALLATIONISTOBEADJUSTEDTOOBTAINTEMPERATURERISEWITHINTHERANGESPECIFIEDONTHERATINGPLATE.
5. The chart is for information only. For satisfactory operation, external static pressure must not exceed value shown on rating plate. The shaded area indicates ranges in excess
of maximum external static pressure allowed when heating. The data for 0.6" w.c. to 0.8" w.c. is shown for air conditioning purposes only.
6 The dashed (---) areas indicate a temperature rise not recommended for this model.
7. At higher altitudes, a properly derated unit will have approximately the same temperature rise at a particular CFM, while the ESP at that CFM will be lower.
GMH8***BB
GMH81405DNCC
Tons AC
at0.5" 0.6 0.7 0.8
ESP CFM RISE CFM RISE CFM RISE CFM RISE CFM RISE CFM CFM CFM
HIGH 3.0 1521 ---- 1466 ---- 1414 ---- 1373 ---- 1298 ---- 1243 1164 1075
*MH80403A*B* MED 2.5 1160 26 1160 26 1132 26 1121 26 1082 27 1042 997 925
MED-LO 2.0 961 31 955 31 948 31 932 32 913 33 882 821 803
LOW 1.5 781 38 785 38 781 38 773 38 761 32 745 716 668
HIGH 3.0 1422 31 1352 33 1307 34 1197 37 1157 38 1092 1075 983
*MH80603A*B* MED 2.5 1098 40 1081 41 1051 42 1039 43 1021 44 983 924 868
MED-LO 2.0 919 48 913 49 892 50 847 ---- 829 ---- 818 792 728
LOW 1.5 758 ---- 741 ---- 741 ---- 733 ---- 699 ---- 677 649 626
HIGH 4.0 2134 21 2100 21 2042 22 1975 23 1883 24 1786 1700 1601
*MH80604B*B* MED 3.5 1668 27 1663 27 1656 27 1645 27 1616 28 1549 1492 1391
MED-LO 3.0 1419 31 1426 31 1426 31 1432 31 1419 31 1378 1328 1261
LOW 2.5 1134 39 1145 39 1166 38 1171 38 1160 38 1144 1111 1071
HIGH 3.0 1607 37 1572 38 1547 39 1498 40 1448 41 1390 1302 1222
*MH80803B*B* MED 2.5 1159 51 1156 51 1145 52 1127 53 1108 53 1075 1033 957
MED-LO 2.0 938 63 916 65 916 65 900 ---- 889 ---- 865 829 785
LOW 1.5 785 ---- 766 ---- 743 ---- 730 ---- 709 ---- 683 666 604
HIGH 4.0 2051 ---- 1983 ---- 1895 ---- 1812 ---- 1725 ---- 1627 1530 1439
*MH80804B*B* MED 3.5 1736 ---- 1708 35 1652 36 1611 37 1540 38 1475 1394 1307
MED-LO 3.0 1693 35 1668 36 1459 41 1429 41 1389 43 1339 1274 1204
LOW 2.5 1200 49 1185 50 1180 50 1173 51 1158 51 1125 1125 1080
HIGH 5.0 2290 ---- 2229 ---- 2155 ---- 2047 ---- 1960 ---- 1837 1712 1584
*MH80805C*B* MED 4.0 1852 ---- 1820 ---- 1777 ---- 1719 --- 1641 36 1567 1469 1382
MED-LO 3.5 1615 37 1592 37 1556 38 1516 39 1470 40 1405 1346 1235
LOW 3.0 1290 46 1285 46 1265 47 1235 48 1214 49 1174 1044 904
HIGH 5.0 2323 ---- 2225 ---- 2120 35 2040 36 1974 38 1801 1688 1577
*MH81005C*B* MED 4.0 1858 40 1847 40 1799 41 1744 42 1674 44 1577 1493 1399
MED-LO 3.5 1596 46 1587 47 1571 47 1552 48 1493 50 1397 1326 1217
LOW 3.0 1291 57 1272 58 1261 59 1257 59 1205 61 1168 1118 1060
HIGH 5.0 2469 ---- 2389 ---- 2300 ---- 2223 40 2131 42 2027 1902 1786
*MH81205D*B* MED 4.0 1575 56 1558 57 1545 58 1513 59 1500 59 1419 1354 1271
MED-LO 3.5 1402 63 1380 64 1343 66 1319 67 1296 69 1245 1183 1106
LOW 3.0 1200 ---- 1186 ---- 1161 ---- 1127 ---- 1082 ---- 1042 995 926
HIGH 5.0 2469 42 2389 43 2300 45 2223 47 2131 49 2027 1902 1786
GMH81405DNCC MED 4.0 1575 66 1558 67 1545 67 1513 69 1500 69 1419 1354 1271
MED-LO 3.5 1402 ---- 1380 ---- 1343 ---- 1319 ---- 1296 ---- 1245 1183 1106
LOW 3.0 1200 ---- 1186 ---- 1161 ---- 1127 ---- 1082 ---- 1042 995 926
(CFM & Temperature Rise vs. External Static Pressure)
0.1 0.2 0.3 0.4 0.5
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
TE
M
PE
R
A
TU
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 DIAGRAMS
Wiringis subject tochange. Always referto the wiringdiagram on theunit for themost up-to-date wiring.
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.
GMH8
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'SSPECIFIEDREPLACEMENTPART SMUSTBEUSEDWHENSERVICING.
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
24VA C
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
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.
TYPICALSCHEMATIC
GMH8 ____** MODEL FURNACES
WR 50M56-289 INTEGRATED IGNITION CONTROL
.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
Thisschematicisforreferenceonly. Not all wiring isasshownabove.Alwaysreferto the appropriate wiring diagramfortheunitbeingserviced.