43
NOTES:
1. There is a 3 second pause between alarm code displays.
2. If more than one alarm code exists, all applicable alarm codes will be displayed in numerical sequence.
3. Alarm codes on the IGC will be lost if power to the unit is interrupted.
Table 19 — IGC Board LED Alarm Codes
LED
FLASH
CODE
DESCRIPTION
ACTION TAKEN
BY CONTROL
RESET METHOD PROBABLE CAUSE
On Normal Operation — — —
Off Hardware Failure No gas heating. —
Loss of power to the IGC. Check 5 amp fuse on IGC,
power to unit, 24V circuit breaker, transformer, and
wiring to the IGC.
2 Flashes Limit Switch Fault
Gas valve and igniter
Off.
Indoor fan and
inducer On.
Limit switch closed, or
heat call (W) Off.
High temperature limit switch is open. Check the
operation of the indoor (evaporator) fan motor. Ensure
that the supply-air temperature rise is within the range
on the unit nameplate. Check wiring and limit switch
operation. Check/clean return air filters. Check burner
assembly manifold pressure to ensure proper firing rate.
3 Flashes Flame Sense Fault
Indoor fan and
inducer On.
Flame sense normal.
Power reset for LED
reset.
The IGC sensed a flame when the gas valve should be
closed. The minimum flame sensing microamps is
0.5 ma. Check wiring, flame sensor, and gas valve
operation.
4 Flashes
Four Consecutive Limit
Switch Fault
No gas heating.
Heat call (W) Off. Power
reset for LED reset.
4 consecutive limit switch faults within a single call for
heat. See Limit Switch Fault.
5 Flashes Ignition Fault No gas heating.
Heat call (W) Off. Power
reset for LED reset.
Unit unsuccessfully attempted ignition for 15 minutes.
Check igniter and flame sensor electrode spacing, gaps,
etc. Check flame sense and igniter wiring. Check gas
valve operation and gas supply.
6 Flashes
Induced Draft Motor
Fault
If heat off: no gas
heating.
If heat on: gas valve
Off and inducer On.
Inducer sense normal, or
heat call (W) Off.
Inducer sense On when heat call Off, or inducer sense
Off when heat call On. Check wiring, voltage, and
operation of IGC motor. Check speed sensor wiring to
IGC. Check to ensure Hall Effect wires are not rubbing
against cabinet sheet metal.
7 Flashes Rollout Switch Lockout
Gas valve and igniter
Off.
Indoor fan and
inducer On.
Power reset.
Rollout switch has opened. Check gas valve operation.
Check induced-draft blower wheel is properly secured to
motor shaft.
8 Flashes Internal Control Lockout No gas heating. Power reset.
IGC has sensed internal hardware or software error. If
fault is not cleared by resetting 24 v power, replace the
IGC. Check gas valve connections to IGC terminals.
BRN lead must be on Pin 11. Check that W1, W2 and
Com are correctly connected to the gas valve terminals.
9 Flashes
Temporary Software
Lockout
No gas heating.
1 hour auto reset, or
power reset.
Electrical interference is disrupting the IGC software.
LEGEND
IGC — Integrated Gas Unit Control
LED — Light-Emitting Diode
To Next Page
Loading...
Need help?
General
