27
NOTE: If more than one error mode exists, they will be displayed on the
LED in sequence. Limit switch is ignored in all modes except heating
mode.
COMFORTLINK (FACTORY OPTION)
For details on operating 48HC units equipped with the factory in-
stalled ComfortLink option, refer to “Controls, Start-Up, Opera-
tion and Troubleshooting for 48/50HC 04-28 Single Package
Rooftop Unit with ComfortLink Controls.” See Fig. 51-55 for wir-
ing details.
TYPICAL WIRING DIAGRAMS
See Fig. 56-63 for typical wiring diagrams.
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 7 — IGC Board Faults
LED INDICATION ERROR MODE
ON Normal operation
OFF No power or hardware failure
1 Flash Fan on delay modified
2 Flashes Limit switch fault
3 Flashes Flame sense fault
4 Flashes Consecutive limit switch faults
5 Flashes Ignition lockout fault
6 Flashes Pressure switch fault
7 Flashes Rollout switch fault
8 Flashes Internal control fault
Table 8 — 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.
1 Flash
Indoor Fan On/Off Delay
Modified
5 seconds subtracted from
On delay. 5 seconds
added to Off delay (3 min
max).
Power reset.
High temperature limit switch opens during heat
exchanger warm-up period before fan-on delay
expires. High temperature limit switch opens
within 10 minutes of heat call (W) Off. See Limit
Switch Fault.
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.
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. 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.
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.
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
Downloaded from ManualsNet.com search engine
To Next Page
Loading...
