Table ll--Troubleshoofing Guide-Heating
SYMPTOM CAUSE REMEDY
Water in gas line Drain. Install drip leg.
No power to furnace Check power supply fuses, wiring or circuit breaker,
Check transformer.
No 20-v power supply to control circuit NOTE: Some transformers have internal over-current protection
that requires a cool-down period to reset.
Burners will not ignite Mis-wired or loose connections Check all wiring and wire nut connections
Check flame ignition and sense electrode positioning,
Misaligned spark electrodes 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-
No gas at main burners fore attempting to light unit,
2. Check gas valve,
Dirty air filter Clean or replace filter as necessary
Gas input to furnace too low Check gas pressure at manifold match with that on unit nameplate
Unit undersized for application Replace with proper unit or add additional unit
Inadequate heating Restricted airflow Clean or replace filter, Remove any restriction.
Check rotation of blower, temperature rise of unit, Adjust as neces-
Limit switch cycles main burners
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
Poor flame characteristics Incomplete combustion results in: Aldehyde odors, or manifold pressure).
carbon monoxide, sooting flame, floating flame
4. Check burner alignment.
5. Inspect heat exchanger for blockage. Clean as necessary,
Table 12--Troubleshooting Guide-LED Status Codes
SYMPTOM CAUSE REMEDY
Check 5-amp fuse son IGC*, power to unit, 24-v circuit breaker,
Hardware failure and transformer. Units without a 24-v circuit breaker have an inter-
(LED OFF) Loss of power to control module (iGC)*, nal overload in the 24-v transformer, If the overload trips, allow 10
minutes for automatic reset.
Limit switch faults Check the operation of the indoor (evaporator) fan motor. Ensure
(LED 2 flashes) High temperature limit switch is open, that the supply-air temperature rise is in accordance with the range
on the unit nameplate. Clean or replace filters,
Flame sense fault
The IGC sensed flame that should not be present. Reset unit, If problem persists, replace control board,
(LED 3 flashes)
4 consecutive limit switch Check the operation of the indoor (evaporator) fan motor and that
faults Inadequate airflow to unit, supply-air temperature rise agrees with range on unit nameplate
(LED 4 flashes) information,
Ignition lockout Check ignitor and flame sensor electrode spacing, gaps, etc, En-
(LED 5 flashes) Unit unsuccessfully attempted ignition for 15 minutes, sure that fame sense and ignition wires are properly terminated,
Verify that unit is obtaining proper amount of gas.
Check for proper voltage. If motor is operating, check the speed
Induced-draft motor fault IGC does not sense that induced-draft motor is operat- sensor ptug/IGC Terminal J2 connection, Proper connection:
(LED 6 flashes) ing,* PIN 1 - White
PIN 2 - Red
PIN 3 - Black
Rollout switch will automatically reset, but IGC will continue to
Roliout switch fault lockout unit. Check gas valve operation. Ensure that induced-draft
(LED 7 flashes) Rollout switch has opened, blower wheel is properly secured to motor shaft, inspect heat ex-
changer. Reset unit at unit disconnect.
Internal control fault Microprocessor has sensed an error in the software or If error code is not cleared by resetting unit power, replace the
(LED 8 flashes) hardware. IGC*.
Temporary software lockout Reset 24-v. to control board or turn thermostat oft, then on again,
(LED 9 flashes) Electrical interference impeding IGC software Fault will automatically reset itself in one (1) hour,
WARNING/!_ : If the IOC illI1st be replaced, be stlre to ground yotlrself to dissipate any electrical charge that my be present before handling new control board. The IOC is
sensitive to static electricity and m) be damaged if the necessary precautions are not taken.
IMPORTANT: Refer to Table 11 Troubleshooting Guide Heating for additional troubleshooting analysis.
LEGEND
IG( Integrated Gas Unit Controller
LED Light Emitting Diode
27
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