Carrier 48/50PD05 User Manual
Page 36
36
Table 13 — 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
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 14 — Electric Heat Service Analysis
PROBLEM
CAUSE
REMEDY
Heat Will Not Turn On.
Unit is not configured for heat.
Check heating configurations using ComfortLinkt
Scrolling Marquee.
Active alarm.
Check active alarms using
ComfortLink™ Scrolling
Marquee.
No power to unit.
Check power supply, fuses, wiring, and circuit breakers.
Unit is in minimum heat off---time, or minimum
cool---heat changeover time.
Check using
ComfortLinkt Scrolling Marquee.
Heat forced off in Service Test.
Check using
ComfortLinkt Scrolling Marquee. Turn
Service Test mode off.
No 24 vac at heater contactor.
Check transformer, circuit breaker, auto---reset limit
switches on heater, and manual---reset limit switches (LS)
on indoor fan housing.
Open temperature limit switch on heater.
Check minimum airflow. Check limit switch when it is cool,
replace if not.
Inadequate Heating.
Dirty air filters.
Replace air filters.
Bad heater elements.
Power off unit and remove high voltage wires. Check
resistance of element, replace if open.
Occupancy schedule set point set too low.
Check setpoints and adjust if necessary.
Heat undersized for load.
Decrease load or increase size of heater.
Restricted or low airflow.
Remove restriction, verify proper fan speed operation, and
check SAT compared to the SAT heating limits.
Too much outdoor air.
Check economizer position and configuration. Adjust
minimum position if needed using ComfortLinkt Scrolling
Marquee. Verify proper fan speed operation.
Limit switch cycles heaters.
Check rotation of blower, temperature rise of unit, and
minimum airflow. Adjust as needed.
Heat Will Not Turn Off.
Unit is in minimum heat on---time.
Check using
ComfortLinkt Scrolling Marquee.
Occupancy schedule set point still calling for
Heating.
Check using
ComfortLinkt Scrolling Marquee.
Unit running in Service Test mode.
Check using
ComfortLinkt Scrolling Marquee.
Heater contactor failed.
Power off unit. Check contactor and replace if closed.
LEGEND
SAT
--
Supply Air Temperature
48/
50P
D