Carrier 50PD05 Operating And Service Instructions page 36

Table 13 -- IGC Board LED Alarm Codes
LED ACTION TAKEN BY
FLASH DESCRIPTION RESET METHOD PROBABLE CAUSE
CONTROL
CODE
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 5 seconds subtracted from Power reset. High temperature limit switch opens during heat
Modified On delay, exchanger warm-up period before fan-on delay
5 seconds added to Off expires.
delay (3 min max). 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. Limit switch closed, or High temperature limit switch is open. Check the
Indoor fan and inducer On. heat call (W) Off. 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. The IGC sensed a flame when the gas valve should
Power reset for LED reset, be c!osed. Check wiring, flame sensor, and gas
valve operation.
4 Flashes Four Consecutive Limit Switch No gas heating. Heat call (W) Off. 4 consecutive limit switch faults within a single call
Fault Power reset for LED reset, for heat. See Limit Switch Fault.
5 Flashes Ignition Fault No gas heating. Heat call (W) Off. Unit unsuccessfully attempted ignition for 15 minutes.
Power reset for LED reset. 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. Inducer sense normal, or Inducer sense On when heat call Off, or inducer
If heat on: gas valve Off heat call (W) Off. sense Off when heat call On. Check wiring, voltage,
and inducer On. and operation of IGC motor. Check speed sensor
wiring to IGC.
7 Flashes Rol!out Switch Lockout Gas valve and igniter Off. Power reset. Rollout switch has opened. Check gas valve
Indoor fan and inducer On. operation. Check induced-draft blower whee! 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 Electrical interference is disrupting the IGC
3ower reset, software.
LEGEND
IGC - Integrated Gas [7nit 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
Heat Will Not Turn On.
CAUSE
Unit is not configured for heat.
Active alarm.
No power to unit.
Unit is in minimum heat off-time, or minimum
cool- heat changeover time.
Heat forced off in Service Test.
No 24 vac at heater contactor.
Open temperature limit switch on heater.
Dirty air filters.
Bad heater elements.
Inadequate Heating.
Occupancy schedule set point set too low.
Heat undersized for load.
Restricted or low airflow.
Too much outdoor air.
Limit switch cycles heaters.
Heat Will Not Turn Off, Unit is in minimum heat on-time.
Occupancy schedule set point still calling for
Heating.
LEGEND
SAT Supply Air Temperature
REMEDY
Check heating configurations using ComfortLink _
Scrolling Marquee.
Check active alarms using ComfortLink T,, Scrolling
Marquee.
Check power supply, fuses, wiring, and circuit breakers.
Check using ComfortLink _' Scrolling Marquee.
Check using ComfortLink _' Scrolling Marquee. Turn
Service Test mode off.
Check transformer, circuit breaker, auto-reset limit
switches on heater, and manual-reset limit switches (LS)
on indoor fan housing.
Check minimum airflow. Check limit switch when it is cool,
replace if not.
Replace air filters.
Power off unit and remove high voltage wires. Check
resistance of element, replace if open.
Check setpoints and adjust if necessary.
Decrease load or increase size of heater.
Remove restriction, verify proper fan speed operation, and
check SAT compared to the SAT heating limits.
Check economizer position and configuration. Adjust
minimum position if needed using ComfortLink _' Scrolling
Marquee. Verify proper fan speed operation.
Check rotation of blower, temperature rise of unit, and
minimum airflow. Adjust as needed.
Check using ComfortLink _' Scrolling Marquee.
Check using ComfortLink _' Scrolling Marquee.
Unit running in Service Test mode. Check using ComfortLink _' Scrolling Marquee.
Heater contactor failed. Power off unit. Check contactor and replace if closed.
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