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by removing one setscrew. Then remove nuts that hold
motor to mounting plate.
6. To reinstall, reverse the procedure outlined above.
Step 12 —Limit Switch
Remove blower access panel (Fig. 8). Limit switch is located on
the fan deck.
Step 13 —Burner Ignition
Unit is equipped with a direct spark ignition 100% lockout
system. Integrated Gas Unit Controller (IGC) is located in the
control box (Fig. 13). A single LED on the IGC provides a visual
display of operational or sequential problems when the power
supply is uninterrupted. The LED can be observed through the
viewport. When a break in power occurs, the IGC will be reset
(resulting in a loss of fault history) and the evaporator fan on/off
times delay will be reset. During servicing, refer to the label on
the control box cover or Table 40 for an explanation of LED error
code descriptions.
If lockout occurs, unit may be reset by interrupting power supply
to unit for at least 5 seconds.
Table 40—LED Error Code Description*
LED INDICATION ERROR CODE DESCRIPTION
ON
Normal Operation
OFF
Hardware Failure
1Flash†
Evaporator Fan On/Off Delay Modified
2Flashes
Limit Switch Fault
3Flashes
Flame Sense Fault
4Flashes
4 Consecutive Limit Switch Faults
5Flashes
Ignition Lockout Fault
6Flashes
Induced-Draft Motor Fault
7Flashes
Rollout Switch Fault
8Flashes
Internal Control Fault
9Flashes
Software Lockout
LEGEND
LED — Light-Emitting Diode
*A 3-second p ause exists b etween LED error code flashes. I f more than
one error code exists, all applicable codes will be displayed in numeri-
cal sequence.
†Indicates a codethat isnot an error. Theunit will continue to operate
when this code is displayed.
IMPORTANT: Refer to Troubleshooting Tables for additional
information.
Step 14 —Main Burners
At the beginning of each heating s eason, inspect for deterioration
or blockage due to corrosion or other causes. Observe the main
burner flames and adjust, if necessary.
FURNACE DAMAGE HAZARD
Failure to follow t his caution may result in reduced furnace
life.
When servicing gas train, do not hit or plug orifice spuds.
CAUTION
!
REMOVAL AND REPLACEMENT OF GAS TRAIN
(See Fig. 72 and
73)
1. Shut off manual gas valve.
2. Shut off power to unit, tag disconnect.
3. Remove compressor access panel.
4. Slide out burner compartment side panel.
5. Disconnect gas piping at unit gas valve.
6. Remove wires connected to gas valve. Mark each wire.
7. Remove induced-draft motor, igniter, and sensor wires at
the Integrated Gas Unit Controller (IGC).
8. Remove the 2 screws that attach the burner rack to the
vestibule plate.
9. Remove the gas valve bracket.
10. Slide the burner tray out of the unit (Fig. 73).
11. To reinstall, reverse the procedure outlined above.
INDUCED-
DRAFT
MOTOR
MOUNTING
PLATE
INDUCED-
DRAFT
MOTOR
MANIFOLD
PRESSURE
TAP
VESTIBULE
PLATE
FLUE
EXHAUST
ROLLOUT
SWITCH
BLOWER
HOUSING
GAS
VALVE
BURNER
SECTION
C06152
Fig. 72 --- Burner Section Details
C06153
Fig. 73 --- Burner Tray Details
12. Reinstall burners on rack.
48HE,HJ