Carrier 48HC D17 Series Service And Maintenance Instructions page 52

LED
FLASH DESCRIPTION
CODE
On Normal Operation
Off Hardware Failure
2
Limit Switch Fault
Flashes
3
Flame Sense Fault
Flashes
4 Four Consecutive Limit
Flashes Switch Fault
5
Ignition Fault
Flashes
6 Induced Draft Motor
Flashes Fault
7
Rollout Switch Lockout
Flashes
8
Internal Control Lockout
Flashes
9 Temporary Software
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 17 – IGC Board LED Alarm Codes
ACTION TAKEN BY
RESET METHOD
CONTROL
—
No gas heating.
Gas valve and igniter
Off. Limit switch closed,
Indoor fan and inducer or heat call (W) Off.
On.
Flame sense normal.
Indoor fan and inducer
Power reset for LED
On.
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
Inducer sense
heating.
normal, or heat call
If heat on: gas valve
(W) Off.
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
No gas heating.
power reset.
52
PROBABLE CAUSE
—
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 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.
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 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. Check to ensure Hall Effect wires are
not rubbing against cabinet sheet metal.
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.
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.
Electrical interference is disrupting the
IGC software.
—