User`s manual

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40
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Table 21 — LED Error Code Service Analysis
IMPORTANT:
Refer to Table 20 — Heating Service Analysis for addi-
tional troubleshooting analysis.
LEGEND
PROBLEM CAUSE REMEDY
Hardware failure.
(LED OFF)
Loss of power to control module (IGC). 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.
Fan ON/OFF delay
modified (LED/
FLASH)
High limit switch opens during heat
exchanger warm-up period before fan-on
delay expires.
Limit switch opens within three minutes
after blower-off delay timing in Heating mode.
Ensure unit is fired on rate and temperature rise is correct.
Ensure unit’s external static pressure is within application
guidelines.
Limit switch fault.
(LED 2 flashes)
High temperature limit switch is open. Check the operation of the indoor (evaporator) fan motor. En-
sure that the supply-air temperature rise is in accordance with
the range on the unit nameplate.
Flame sense fault.
(LED 3 flashes)
The IGC sensed flame that should not be present. Reset unit. If problem persists, replace control board.
4 consecutive limit
switch faults.
(LED 4 flashes)
Inadequate airflow to unit. Check operation of indoor (evaporator) fan motor and that
supply-air temperature rise agrees with range on unit name-
plate information.
Ignition lockout.
(LED 5 flashes)
Unit unsuccessfully attempted ignition for 15 minutes. 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.
Induced-draft motor fault.
(LED 6 flashes)
IGC does not sense that induced-draft motor is
operating.
Check for proper voltage. If motor is operating, check the
speed sensor plug/IGC Terminal J2 connection. Proper
connection: PIN 1 — White, PIN 2 — Red, PIN 3 — Black.
Rollout switch fault.
(LED 7 flashes)
Rollout switch has opened. 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.
Internal control fault.
(LED 8 flashes)
Microprocessor has sensed an error in the
software or hardware.
If error code is not cleared by resetting unit power, replace the
IGC.
WARNING:
If the IGC must be replaced, be sure to
ground yourself to dissipate 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 pre-
cautions are not taken.
IGC —
Integrated Gas Unit Controller
LED —
Light-Emitting Diode