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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.
1Flash 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.
2Flashes 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.
3Flashes Flame Sense Fault Indoor fan and inducer On. Flame sense normal.
Power reset for LED reset.
TheIGCsensedaflamewhenthegasvalveshould
be closed. Check wiring, flame sensor, and gas
valve operation.
4Flashes 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.
5Flashes 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.Checkflamesenseandigniterwiring.
Check gas valve operation and gas supply.
6Flashes 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.
7Flashes 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.
8Flashes 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.
9Flashes 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 a3--second pause between alarm code displays.
2. If more than one alarm code exists, allapplicable alarm codes will be displayed in numerical sequence.
3. Alarm codeson the IGCwillbe 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 Com fortLinkt Scrolling Marquee. Turn
ServiceTestmodeoff.
No 24 vac at heater contactor. Check transformer, circuit breaker, auto---reset limit
switches on heater, and manual---reset limit switches (LS)
on indoor
f
an housin
g
.
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
48/50PD