Troubleshooting; Led Error Code Service Analysis; Heating Service Analysis - Carrier 48TF004-007 Installation, Start-Up And Service Instructions Manual

PROBLEM
Hardware failure. Loss of power to control module (IGC).
(LED OFF)
Limit switch fault. High temperature limit switch is open.
(LED 2 flashes)
The IGC sensed flame that should not be
Flame sense fault.
(LED 3 flashes) present.
4 consecutive limit Inadequate airflow to unit.
switch trips.
(LED 4 flashes)
Ignition lockout. Unit unsuccessfully attempted ignition for
(LED 5 flashes) 15 minutes.
Induced-draft motor fault. IGC does not sense that induced-draft motor is
(LED 6 flashes) operating.
Rollout switch fault. Rollout switch has opened.
(LED 7 flashes)
Internal control fault. Microprocessor has sensed an error in the soft-
(LED 8 flashes) ware or hardware.
If the IGC must be replaced, be sure to ground yourself to dissi-
pate any electrical charge that may be present before handling
new control board. The IGC is sensitive to static electricity and
may be damaged if the necessary precautions are not taken.
PROBLEM
Burners will not ignite. Misaligned spark electrodes.
No gas at main burners.
Water in gas line.
No power to furnace.
No 24 v power supply to control circuit.
Miswired or loose connections.
Burned-out heat anticipator in thermostat. Replace thermostat.
Broken thermostat wires.
Inadequate heating. Dirty air filter.
Gas input to unit too low.
Unit undersized for application.
Restricted airflow.
Blower speed too low.
Limit switch cycles main burners.
Too much outdoor air.
Poor flame characteristics. Incomplete combustion (lack of combus-
tion air) results in:
Aldehyde odors, CO, sooting flame, or
floating flame.
Burners will not turn off. Unit is locked into Heating mode for a one
minute minimum.

TROUBLESHOOTING

Table 32 — LED Error Code Service Analysis
CAUSE
Table 33 — Heating Service Analysis
CAUSE
Check flame ignition and sensor electrode positioning. Adjust as needed.
44
Check 5 amp fuse on IGC, power to unit, 24-v circuit breaker,
and transformer. Units without a 24-v circuit breaker have an
internal overload in the 24-v transformer. If the overload trips,
allow 10 minutes for automatic reset.
Check the operation of the indoor (evaporator) fan motor.
Ensure that the supply-air temperature rise is in accordance
with the range on the unit nameplate.
Reset unit. If problem persists, replace control board.
Check operation of indoor (evaporator) fan motor and that
supply-air temperature rise agrees with range on unit name-
plate information.
Check ignitor and flame sensor electrode spacing, gaps, etc.
Ensure that flame sense and ignition wires are properly termi-
nated. Verify that unit is obtaining proper amount of gas.
Check for proper voltage. If motor is operating, check the
speed sensor plug/IGC Terminal J2 connection. Proper con-
nection: PIN 1 — White, PIN 2 — Red, PIN 3 — Black.
Rollout switch will automatically reset, but IGC will continue to
lock out unit. Check gas valve operation. Ensure that induced
draft blower wheel is properly secured to motor shaft. Reset
unit at unit disconnect.
If error code is not cleared by resetting unit power, replace the
IGC.
IMPORTANT: Refer to Table 19 — Heating Service Analysis
for additional troubleshooting analysis.
LEGEND
IGC — Integrated Gas Unit Controller
LED — Light-Emitting Diode
Check gas line for air, purge as necessary. After purging gas line of air,
allow gas to dissipate for at least 5 minutes before attempting to relight
unit.
Check gas valve.
Drain water and install drip leg to trap water.
Check power supply, fuses, wiring, and circuit breaker.
Check transformer. Transformers with internal overcurrent protection
require a cool down period before resetting.
Check all wiring and wire nut connections.
Run continuity check. Replace wires, if necessary.
Clean or replace filter as necessary.
Check gas pressure at manifold. Clock gas meter for input. If too low,
increase manifold pressure, or replace with correct orifices.
Replace with proper unit or add additional unit.
Clean filter, replace filter, or remove any restrictions.
Use high speed tap, increase fan speed, or install optional blower, as
suitable for individual units.
Check rotation of blower, thermostat heat anticipator settings, and tem-
perature rise of unit. Adjust as needed.
Adjust minimum position.
Check economizer operation.
Check all screws around flue outlets and burner compartment. Tighten
as necessary.
Cracked heat exchanger.
Overfired unit — reduce input, change orifices, or adjust gas line or man-
ifold pressure.
Check vent for restriction. Clean as necessary.
Check orifice to burner alignment.
Wait until mandatory one minute time period has elapsed or re-
set power to unit.
REMEDY
REMEDY