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SERVICE AND TECHNICAL SUPPORT MANUAL

Gas Furnace: (F/G)9MVE

Specifications  subject to change without notice.

440 04 4801 03

21

12. Spin the blower wheel by hand to verify that the wheel

does not rub on the housing.

13. Reinstall blower assembly in furnace.
14. Reinstall 2 screws securing blower assembly to blower

deck.

15. Reconnect blower leads to furnace control. Refer to

furnace wiring diagram, and connect thermostat leads if

previously disconnected.

NOTE

:  Be sure to attach ground wire and reconnect blower

harness plugs to blower motor.

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal

injury or death.
Blower door switch opens 115

v power to control. No

component operation can occur unless switch is closed.

Caution must be taken when manually closing this

switch for service purposes.

!

WARNING

16. Downflow or horizontal furnaces with vent pipe through

furnace only:
a. Install and connect short piece of vent pipe inside

furnace to existing vent.

b. Connect vent connector to vent elbow.

17. Turn on electrical supply. Manually close blower door

switch. Use a piece of tape to hold switch closed. Check

for proper rotation and speed changes between heating

and cooling by jumpering R to G and R to Y/Y2 on

furnace control thermostat terminals. If outdoor

temperature is below 70

_

F (21

_

C), turn off circuit breaker

to outdoor unit before running furnace in the cooling

cycle. Turn outdoor circuit breaker on after completing

cooling cycle. (See 

Figure 4

)

NOTE

:  If R

W/W1 thermostat terminals are jumpered at the

time blower door switch is closed, blower will run for 90 sec

before beginning a heating cycle.

a. Perform component self

test as shown at the bottom

of the SERVICE label, located on the control door.

b. Verify blower is rotating in the correct direction

18. If furnace is operating properly, RELEASE BLOWER

DOOR SWITCH. Remove any jumpers or reconnect any

disconnected thermostat leads. Replace blower door.

19. Turn on gas supply and cycle furnace through one

complete heating cycle. Verify the furnace temperature

rise as shown in Adjustments Section. Adjust

temperature rise as shown in Adjustments Section.

Cleaning Burners and Flame Sensor

The following items must be performed by a qualified service

technician. If the burners develop an accumulation of light dirt

or dust, they may be cleaned by using the following procedure:

NOTE

:  Use a back-up wrench on the gas valve to prevent the

valve from rotating on the manifold or damaging the mounting

to the burner assembly.

ELECTRICAL SHOCK AND FIRE HAZARD

Failure to follow this warning could result in personal

injury, death, and/or property damage.
Turn off the gas and electrical supplies to the furnace

and install lockout tag before performing any

maintenance or service. Follow the operating

instructions on the label attached to the furnace.

!

WARNING

Refer to 

Figure 10

.

1. Disconnect power at external disconnect, fuse or circuit

breaker.

2. Turn off gas at external shut-off or gas meter.
3. Remove control door and set aside.
4. Turn electric switch on gas valve to OFF.
5. Disconnect the gas pipe from gas valve and remove pipe

from the furnace casing.

6. Remove individual wires from terminals on gas valve (All

other models).

7. Disconnect Hot Surface Igniter (HSI) wires from HSI.
8. Disconnect Flame Sensor wire from Flame Sensor.
9. Support the manifold and remove the 4 screws that

secure the manifold assembly to the burner assembly

and set aside. Note the location of the green/yellow wire

and ground terminal.

10. Inspect the orifices in the manifold assembly for

blockages or obstructions. Remove orifice and clean or

replace orifice.

11. Remove the four screws that attach the top plate of the

casing to the furnace.

12. Raise top plate up slightly and prop it up with a small

piece of wood or folded cardboard.

13. Support the burner assembly and remove the screws

that attach the burner assembly to the heat exchanger

cell panel.

14. Remove wires from both rollout switches.
15. Slide one

piece burner out of slots on sides of burner

assembly.

16. Remove the flame sensor from the burner assembly.
17. (Optional) Remove the Hot Surface Igniter (HSI) and

bracket from the burner assembly.

18. Check igniter resistance. Nominal resistance is 40 to 70

ohms at room temperature and is stable over the life of

the igniter.

19. Clean burner with a brush and a vacuum.
20. Clean the flame sensor with fine steel wool (0000 grade).

Do not use sand paper or emery cloth.

To reinstall burner assembly:

1. Install the Hot Surface Igniter (HSI) and bracket in burner

assembly.

2. Install flame sensor on burner.

Summary of Contents for A3 Series

Page 1: ...tures or product labels The signal word WARNING is used throughout this manual in the following manner Safety alert symbol When you see this symbol on the unit and in instructions or manuals be alert...

Page 2: ...eath WARNING signifies hazards which could result in personal injury or death CAUTION is used to identify unsafe practices which may result in minor personal injury or product and property damage NOTE...

Page 3: ...in Connected Condensate Drain Trapped Manual Gas Shut off Upstream of Furnace Drip Leg Gas Valve turned ON Type of Gas Natural Propane Filter Type and Size Shade in Final Furnace Settings Below O N O...

Page 4: ...l Setup Switches SW1 The furnace control has 8 setup switches that may be set to meet the application requirements To set these setup switches for the appropriate requirement 1 Remove blower door 2 Lo...

Page 5: ...soap solution made specifically for the detection of leaks to check all connections A fire or explosion may result causing property damage personal injury or loss of life WARNING Adjustments FIRE HAZ...

Page 6: ...0 Btu cu ft Specific gravity 0 62 Therefore Orifice No 44 Furnace is shipped with No 44 orifices In this example all main burner orifices are the correct size and do not need to be changed to obtain p...

Page 7: ...ease input rate Figure 3 Redundant Automatic Gas Control Valve 2 Stage without Tower Pressure Ports ON OFF Switch Regulator Seal Cap RegulatorAdjustment Regulator Seal Cap under Cap 1 2 NPT Outlet 1 8...

Page 8: ...s warning could result in personal injury death and or property damage Manifold pressure tap set screw must be tightened or 1 8 in NPT pipe plug must be installed to prevent gas leaks WARNING c Tighte...

Page 9: ...300 21 171 343 857 62 58 116 290 22 164 327 818 64 56 112 281 23 157 313 783 66 54 109 273 24 150 300 750 68 53 106 265 25 144 288 720 70 51 103 257 26 138 277 692 72 50 100 250 27 133 267 667 74 48...

Page 10: ...43 3 8 1 6 42 3 2 1 4 850 44 3 8 1 6 43 3 5 1 5 43 3 6 1 5 43 3 7 1 6 875 44 3 6 1 5 44 3 7 1 6 43 3 4 1 4 43 3 5 1 5 4000 900 44 3 4 1 4 44 3 5 1 5 44 3 7 1 5 44 3 8 1 6 1219 925 44 3 2 1 4 44 3 4 1...

Page 11: ...re and airflow FURNACE DAMAGE HAZARD Failure to follow this caution may result in S Overheating the heat exchangers or condensing flue gases in heat exchanger areas not designed for condensate S Short...

Page 12: ...r off delay See Table 4 and Figure 4 Figure 5 Table 4 Blower Speed Taps DESIRED HEATING MODE BLOWER OFF DELAY SEC SETUP SWITCH SW1 7 and 8 POSITION 90 OFF OFF 120 ON OFF 150 OFF ON 180 ON ON Adjust Co...

Page 13: ...r refer to unit wiring diagram TWN 1 CFM 2 3 4 5 6 7 8 SW2 CF AC SW2 1 Twining OFF Allows for selection of furnace Main OFF or Secondary ON when Twinned furnace setup is required See kit instructions...

Page 14: ...this method to check limit control it can be established that limit is functioning properly and will operate if there is a restricted return air supply or motor failure If limit control does not funct...

Page 15: ...FF OFF ON 605 565 510 455 420 See note 4 OFF ON OFF 785 750 705 675 630 585 See note 4 OFF ON ON 955 920 895 860 825 785 755 720 685 650 ON OFF OFF 1135 1110 1080 1055 1020 990 935 880 825 745 ON OFF...

Page 16: ...0 22 Clg Default OFF OFF OFF 2010 1960 1910 1850 1800 1750 1690 1645 1565 1480 Cooling SW2 OFF OFF ON 1015 805 645 550 480 See note 4 OFF ON OFF 1075 975 915 835 765 See note 4 OFF ON ON 1205 1135 105...

Page 17: ...itioned air is discharged upward Since this furnace can be installed in any of the 4 positions shown in Figure 7 you must revise your orientation to component location accordingly Figure 7 Multipoise...

Page 18: ...isconnecting the limit switch To retrieve Status Codes follow the procedure below 2 Turn Setup Switch SW1 1 ON 3 Manually close blower door switch 4 Control will flash up to 7 Status Codes 5 The last...

Page 19: ...eason Service as necessary 4 Inspect burner compartment before each heating season for rust corrosion soot or excessive dust If necessary have furnace and burner serviced by a qualified service agency...

Page 20: ...balance will be affected 7 If greasy residue is present on blower wheel remove wheel from the blower housing and wash it with an appropriate degreaser To remove wheel a Mark blower wheel location on s...

Page 21: ...following items must be performed by a qualified service technician If the burners develop an accumulation of light dirt or dust they may be cleaned by using the following procedure NOTE Use a back up...

Page 22: ...the Hot Surface Igniter NOTE Use propane resistant pipe dope to prevent leaks Do not use Teflon tape 13 Install the gas pipe to the gas valve Figure 12 Igniter Position Side View L12F041 2 in 2 5 mm...

Page 23: ...quired Verify a condensate trap gasket is included in the service kit or obtain one from your local distributor 1 Disconnect power at external disconnect fuse or circuit breaker 2 Turn off gas at exte...

Page 24: ...wiring diagram and reconnect wires to flame rollout switch gas valve igniter and flame sensor 10 Turn on gas and electrical supplies to furnace 11 Check furnace operation through two complete heat op...

Page 25: ...uart of anti freeze solution into the funnel tube Antifreeze should run through the collector box overfill condensate trap and flow to an open drain 8 Replace the rubber plug in the port on the collec...

Page 26: ...SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace F G 9MVE Specifications subject to change without notice 440 04 4801 03 26 Figure 15 Service Label 340688 2 REV D...

Page 27: ...SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace F G 9MVE Specifications subject to change without notice 27 440 04 4801 03 Figure 16 Wiring Diagram 340688 2 REV D...

Page 28: ...t flashes When done put setup switch SW1 1 in the OFF position Was there a previous status code other than the heartbeat Go to section below for the status code that was flashed Does the control respo...

Page 29: ...t check manifold pressure If OK check burner carryover and flame sensor location Clean flame sensor with fine steel wool and recheck current Nominal current is 4 0 to 6 0 microamps Is current near typ...

Page 30: ...t high speed and the high heat pressure switch relay HPSR is de energized to close the NC contact When sufficient pressure is available the high heat pressure switch HPS closes and the high heat gas v...

Page 31: ...tor BLWM will continue operating at cooling airflow for an additional 90 seconds Jumper Y Y2 to DHUM to reduce the cooling off delay to 5 seconds See Figure 4 b Two Stage Thermostat and Two Speed Cool...

Page 32: ...eat pump the furnace control automatically changes the timing sequence to avoid long blower off times during demand defrost cycles Whenever W W1 is energized along with Y1 or Y Y2 the furnace control...

Page 33: ...801 03 Figure 20 Variable Speed Furnace with Single Stage Heat Pump Dual Fuel L09F026 NOTE 9 Figure 21 Variable Speed Furnace with Two Stage Heat Pump Dual Fuel L09F028 NOTE 9 Figure 22 Variable Speed...

Page 34: ...stallation Instructions for additional information and setup procedure 4 When using a Humidity Sensing Thermostat set DEHUMIDIFY OPTIONS to H DE ENRGZD FOR DEHUM 5 Optional connection If wire is conne...

Page 35: ...ector box Condensate trap Condensate trap elbow Gaskets WARNING FIRE EXPLOSION ELECTRICAL SHOCK AND CARBON MONOXIDE POISONING HAZARD Failure to follow this warning could result in dangerous operation...

Page 36: ...ed X ECM S Single stage T Two stage FEATURE B Base AFUE Efficiency E Extra AFUE Efficiency C Communicating D Dual Certified 2 pipe or 1 pipe R 2 pipe only S Single stage T Two stage N Standard L Low N...

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