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39
Flue Gas Passageways —
To inspect the flue collec-
tor box and upper areas of the heat exchanger:
1. Remove the combustion blower wheel and motor assem-
bly according to directions in Combustion-Air Blower
section below.
2. Remove the flue cover to inspect the heat exchanger.
3. Clean all surfaces as required using a wire brush.
Combustion-Air Blower —
Clean periodically to as-
sure proper airflow and heating efficiency. Inspect blower
wheel every fall and periodically during heating season. For the
first heating season, inspect blower wheel bimonthly to deter-
mine proper cleaning frequency.
To inspect blower wheel, shine a flashlight into draft hood
opening. If cleaning is required, remove motor and wheel as
follows:
1. Slide burner access panel out.
2. Remove the 6 screws that attach induced-draft motor
housing to vestibule plate (Fig. 52).
3. The blower wheel can be cleaned at this point. If addi-
tional cleaning is required, continue with Steps 4 and 5.
4. To remove blower from the motor shaft, remove
2 setscrews.
5. To remove motor, remove the 4 screws that hold blower
housing to mounting plate. Remove the motor cooling fan
by removing one setscrew. Then remove nuts that hold
motor to mounting plate.
6. To reinstall, reverse the procedure outlined above.
Limit Switch —
Remove blower access panel (Fig. 6).
Limit switch is located on the fan deck.
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. 11). Module contains a
self-diagnostic LED (light-emitting diode). A single LED on
the IGC provides a visual display of operational or sequential
problems when the power supply is interrupted. When a break
in power occurs, the module will be reset (resulting in a loss of
fault history) and the indoor (evaporator) fan ON/OFF times
will be reset. For additional information, refer to the Start-Up,
Heating section on page 34. The LED error code can be ob-
served through the viewport. During servicing refer to the label
on the control box cover or Table 25 for an explanation of LED
error code descriptions.
If lockout occurs, unit may be adjusted by interrupting pow-
er supply to unit for at least 5 seconds.
Table 25 — LED Error Code Description*
LEGEND
*A 3-second pause exists between LED error code flashes. If more
than one error code exists, all applicable codes will be displayed in
numerical sequence.
†Indicates a code that is not an error. The unit will continue to oper-
ate when this code is displayed.
**Indicates internal processor fault and will reset itself in 1 hour.
LED INDICATION ERROR CODE DESCRIPTION
ON
Normal Operation
OFF
Hardware Failure
1 Flash†
Evaporator Fan On/Off Delay Modified
2 Flashes
Limit Switch Fault
3 Flashes
Flame Sense Fault
4 Flashes
4 Consecutive Limit Switch Faults
5 Flashes
Ignition Lockout Fault
6 Flashes
Induced-Draft Motor Fault
7 Flashes
Rollout Switch Fault
8 Flashes
Internal Control Fault
9 Flashes**
Temporary 1 hour automatic reset fault
LED —
Light-Emitting Diode
IMPORTANT: Refer to Troubleshooting Tables 26-30 for addi-
tional information.
CIRCUIT NO. 2
CIRCUIT NO. 1
Fig. 51 — Cooling Charging Chart; 48TF014 Units