Carrier 48FC 08-16 Series Service And Maintenance Instructions page 46

LED
FLASH DESCRIPTION
CODE c,d
On Normal Operation
Off Hardware Failure
1 Flash Indoor Fan On/Off Delay
Modified
2 Flashes Limit Switch Fault
3 Flashes Flame Sense Fault
4 Flashes Four Consecutive Limit Switch
Fault
5 Flashes Ignition Fault
6 Flashes Induced Draft Motor
Fault
7 Flashes Rollout Switch Lockout
8 Flashes Internal Control Lockout
9 Flashes Temporary Software Lockout No gas heating.
NOTE(S):
a. Alarm codes on the IGC will be lost if power to the unit is interrupted.
b. If the pressure switch is stuck closed on a W1 call, then the unit will sit idle and do nothing with no fault on the IGC.
c. There is a 3-second pause between alarm code displays.
d. If more than one alarm code exists, all applicable alarm codes will be displayed in numerical sequence.
LEGEND
IGC — Integrated Gas Unit Control
LED — Light-Emitting Diode
Table 12 — IGC Board LED Alarm Codes
ACTION TAKEN BY
CONTROL
—
No gas heating.
5 seconds subtracted from Power reset.
On delay.
Gas valve and igniter Off. Limit switch closed, or
Indoor fan and inducer On. heat call (W) Off.
Indoor fan and inducer On. Flame sense normal.
Power reset for LED reset.
No gas heating. Heat call (W) Off.
Power reset for LED reset.
No gas heating. Heat call (W) Off.
Power reset for LED reset.
If heat off: no gas heating. Inducer sense normal, or
If heat on: gas valve Off and heat call (W) Off.
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
reset.
46
a,b
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 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
—