Carrier 48LC Series Controls, Start-Up, Operation And Troubleshooting page 46

LED
FLASH DESCRIPTION
CODE
On Normal Operation
Off Hardware Failure
Indoor Fan On/Off Delay
1 flash
Modified
2 flashes Limit Switch Fault
3 flashes Flame Sense Fault
Four Consecutive Limit
4 flashes
Switch Fault
5 flashes Ignition Fault
6 flashes Induced Draft Motor Fault
7 flashes Rollout Switch Lockout
8 flashes Internal Control Lockout
Temporary Software
9 flashes
Lockout
LEGEND
IGC — Integrated Gas Unit Control
LED — Light-Emitting Diode
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 22 — IGC Board LED Alarm Codes
ACTION TAKEN BY
CONTROL
—
No gas heating.
5 seconds subtracted
from On delay.
Power reset.
5 seconds added to Off
delay (3 min max).
Gas valve and igniter
Off. Limit switch closed, or heat
Indoor fan and inducer call (W) Off.
On.
Indoor fan and inducer Flame sense normal.
On. Power reset for LED reset.
Heat call (W) Off.
No gas heating.
Power reset for LED reset.
Heat call (W) Off.
No gas heating.
Power reset for LED reset.
If heat off: no gas
heating. Inducer sense normal, or
If heat on: gas valve Off heat call (W) Off.
and inducer On.
Gas valve and igniter
Off.
Power reset.
Indoor fan and inducer
On.
No gas heating. Power reset.
1 hour auto reset, or power
No gas heating.
reset.
46
RESET METHOD
—
Loss of power to the IGC. Check 5 amp fuse
— on IGC, power to unit, 24V circuit breaker,
transformer, and wiring to the IGC.
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.
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.
The IGC sensed a flame when the gas valve
should be closed. Check wiring, flame sensor,
and gas valve operation.
4 consecutive limit switch faults within a single
call for heat. See Limit Switch Fault.
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.
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.
Rollout switch has opened. Check gas valve
operation. Check induced-draft blower wheel is
properly secured to motor shaft.
IGC has sensed internal hardware or software
error. If fault is not cleared by resetting 24 v
power, replace the IGC.
Electrical interference is disrupting the IGC
software.
PROBABLE CAUSE
—