Carrier 48EZ(N)-A Installation Instructions Manual page 40

SYMPTOM
Water in gas line
No power to furnace
No 24--v power supply to control circuit
Burners will not ignite Mis--wired or loose connections
Misaligned spark electrodes
No gas at main burners
Dirty air filter
Gas input to furnace too low
Unit undersized for application
Inadequate heating
Restricted airflow
Limit switch cycles main burners
Incomplete combustion results in: Aldehyde odors,
Poor flame characteristics
carbon monoxide, sooting flame, floating flame
SYMPTOM
No Power or Hardware fail-
ure Loss of power to control module (IGC)*.
(LED OFF)
Limit switch faults
High temperature limit switch is open.
(LED 2 flashes)
Flame sense fault
The IGC* sensed flame that should not be present.
(LED 3 flashes)
4 consecutive limit switch
faults Inadequate airflow to unit.
(LED 4 flashes)
Ignition lockout
Unit unsuccessfully attempted ignition for 15 minutes.
(LED 5 flashes)
Pressure Switch Fault
Open pressure switch.
(LED 6 flashes)
Rollout switch fault
Rollout switch has opened.
(LED 7 flashes)
Internal control fault Microprocessor has sensed an error in the software
(LED 8 flashes) or hardware.
Temporary 1 hr auto reset
Electrical interference impeding IGC software
(LED 9 flashes)
*WARNING : If the IGC must be replaced, be sure to ground yourself to dissipate any electrical charge that my be present before handling new control
board. The IGC is sensitive to static electricity and my be damaged if the necessary precautions are not taken.
IMPORTANT: Refer to Table 12 ---Troubleshooting Guide ---Heating for additional troubleshooting analysis.
LEGEND
IGC—Integrated Gas Unit Controller
LED—Light---Emitting Diode
Table 13 – Troubleshooting Guide–Heating
CAUSE
Table 14 – Troubleshooting Guide–LED Error Codes
CAUSE
40
REMEDY
Drain. Install drip leg.
Check power supply fuses, wiring or circuit breaker.
Check transformer.
NOTE: Some transformers have internal over--current protection
that requires a cool--down period to reset.
Check all wiring and wire nut connections
Check flame ignition and sense electrode positioning.
Adjust as necessary.
1. Check gas line for air. Purge as necessary. NOTE: After purging
gas line of air, wait at least 5 minutes for any gas to dissipate be-
fore attempting to light unit.
2. Check gas valve.
Clean or replace filter as necessary
Check gas pressure at manifold match with that on unit nameplate
Replace with proper unit or add additional unit
Clean or replace filter. Remove any restriction.
Check rotation of blower, temperature rise of unit. Adjust as neces-
sary.
1. Tighten all screws around burner compartment
2. Cracked heat exchanger. Replace.
3. Unit over--fired. Reduce input (change orifices or adjust gas line
or manifold pressure).
4. Check burner alignment.
5. Inspect heat exchanger for blockage. Clean as necessary.
REMEDY
Check 5--amp fuse son 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. Clean or replace filters.
Reset unit. If problem persists, replace control board.
Check the operation of the indoor (evaporator) fan motor and that
supply--air temperature rise agrees with range on unit nameplate
information.
Check ignitor and flame sensor electrode spacing, gaps, etc.
Ensure that fame sense and ignition wires are properly terminated.
Verify that unit is obtaining proper amount of gas.
Verify wiring connections to pressure switch and inducer motor.
Verify pressure switch hose is tightly connected to both inducer
housing and pressure switch. Verify inducer wheel is properly
attached to inducer motor shaft. Verify inducer motor shaft is turn-
ing.
Rollout switch will automatically reset, but IGC* will continue to
lockout unit. Check gas valve operation. Ensure that induced--draft
blower wheel is properly secured to motor shaft. Inspect heat
exchanger. Reset unit at unit disconnect.
If error code is not cleared by resetting unit power, replace the
IGC*.
Reset 24--v. to control board or turn thermostat off, then on again.
Fault will automatically reset itself in one (1) hour.