Carrier 48TF004-007 - Manual (Page 42)

42
Combustion-Air Blower — Clean periodically to
assure 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 access burner section, slide the sliding burner partition
out of the unit.
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 7 screws that attach induced-draft motor
housing to vestibule plate (Fig. 50).
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 the mo-
tor to mounting plate. Remove the motor cooling fan by
removing one setscrew. Then remove nuts that hold mo-
tor to mounting plate.
6. To reinstall, reverse the procedure outlined above.
Limit Switch — Remove blower access panel (Fig. 7).
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). The IGC 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 uninterrupted. When a
break in power occurs, the IGC will be reset (resulting in a loss
of fault history) and the indoor (evaporator) fan ON/OFF times
will be reset. The LED error code can be observed through the
viewport. During servicing refer to the label on the control
box cover or Table 31 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 31 — LED Error Code Description
LEGEND
LED — Light-Emitting Diode
*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.
Main Burners — To access burners, remove burner ac-
cess panel and slide out burner partition. At the beginning of
each heating season, inspect for deterioration or blockage due
to corrosion or other causes. Observe the main burner flames
and adjust, if necessary.
REMOVAL AND REPLACEMENT OF GAS TRAIN
(Fig. 50-52)
1. Shut off manual gas valve.
2. Shut off power to unit.
3. Slide out burner partition.
4. Disconnect gas piping at unit gas valve.
5. Remove wires connected to gas valve. Mark each wire.
6. Remove ignitor wires and sensor wires at the Integrated
Gas Unit Controller (IGC) (see Fig. 11).
7. Remove the 2 screws that attach the burner rack to the
vestibule plate (Fig. 50).
8. Slide the burner tray out of the unit (Fig. 51).
9. To reinstall, reverse the procedure outlined above.
CLEANING AND ADJUSTMENT
1. Remove burner rack from unit as described in Removal
and Replacement of Gas Train section, above.
2. Inspect burners; if dirty, remove burners from rack.
3. Using a soft brush clean burners and cross-over port as
required.
4. Adjust spark gap. See Fig. 52.
5. Reinstall burners on rack.
6. Reinstall burner rack as described in Removal and Re-
placement of Gas Train section, above.
Replacement Parts — A complete list of replacement
parts may be obtained from any Carrier distributor upon
request.
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
IMPORTANT: Refer to Troubleshooting Tables 32-36 for addi-
tional information.
When working on gas train, do not hit or plug orifice
spuds.
INDUCED-
DRAFT
MOTOR
MOUNTING
PLATE
INDUCED-
DRAFT
MOTOR
MANIFOLD
PRESSURE
TAP
VESTIBULE
PLATE
FLUE
EXHAUST
ROLLOUT
SWITCH
BLOWER
HOUSING
GAS
VALVE
BURNER
SECTION
Fig. 50 — Burner Section Details