Carrier 48PG20 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 62

LED FLASH
DESCRIPTION
CODE
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
LEGEND
IGC — Integrated Gas Unit Control
LED — Light-Emitting Diode
PROBLEM
Heat Will Not Turn On.
Inadequate Heating.
Heat Will Not Turn Off.
Table 48 — IGC Board LED Alarm Codes
ACTION TAKEN BY
CONTROL
—
No gas heating.
5 seconds subtracted from On
delay.
5 seconds added to Off delay
(3 min max).
Gas valve and igniter Off.
Indoor fan and inducer On.
Indoor fan and inducer On.
No gas heating.
No gas heating.
If heat off: no gas heating.
If heat on: gas valve Off and
inducer On.
Gas valve and igniter Off.
Indoor fan and inducer On.
No gas heating.
No gas heating.
Table 49 — Electric Heat Service Analysis
CAUSE
Active alarm.
No power to unit.
Unit is in minimum heat off-time, or minimum cool-heat
changeover time.
Thermostat or occupancy schedule setpoint not calling for
heating.
Heat forced off in Service Test mode.
No 24 vac at heater contactor.
Open temperature limit switch on heater.
Dirty air filters.
Thermostat or occupancy schedule setpoint only calling
for W1.
Heat undersized for load.
Restricted airflow
Too much outdoor air.
Limit switch cycles heaters.
Bad heater elements.
Unit is in minimum heat on-time.
Thermostat or occupancy schedule setpoint still calling for
heating.
Heat forced on in Service Test mode.
Heater contactor failed.
RESET METHOD
—
— Loss of power to the IGC. Check 5 amp fuse on IGC,
power to unit, 24V circuit breaker, transformer, and wir-
ing to the IGC.
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.
Limit switch closed, or heat High temperature limit switch is open. Check the opera-
call (W) Off. tion 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.
Flame sense normal. The IGC sensed a flame when the gas valve should be
Power reset for LED reset. closed. Check wiring, flame sensor, and gas valve oper-
ation.
Heat call (W) Off. 4 consecutive limit switch faults within a single call for
Power reset for LED reset. heat. See Limit Switch Fault.
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.
Inducer sense normal, or Inducer sense On when heat call Off, or inducer sense
heat call (W) Off. Off when heat call On. Check wiring, voltage, and oper-
ation of IGC motor. Check speed sensor wiring to IGC.
Power reset. Rollout switch has opened. Check gas valve operation.
Check induced-draft blower wheel is properly secured to
motor shaft.
Power reset. IGC has sensed internal hardware or software error. If
fault is not cleared by resetting 24 v power, replace the
IGC.
1 hour auto reset, or power Electrical interference is disrupting the IGC
reset. software.
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 dis-
played in numerical sequence.
3. Alarm codes on the IGC will be lost if power to the unit is interrupted.
Check active alarms using ComfortLink™ Scrolling Marquee.
Check power supply, fuses, wiring, and circuit breakers.
Check using ComfortLink Scrolling Marquee.
Check using ComfortLink Scrolling Marquee.
Check using ComfortLink Scrolling Marquee. Turn Service Test
mode off.
Check transformer and circuit breaker.
Check auto-reset limit switches on heater.
Check manual-reset limit switch (LS) on heater.
Check minimum airflow. Check limit switch when it is cool,
replace if open.
Replace air filters.
Allow time for W2 to energize.
Decrease load or increase size of heater.
Remove restriction.
Check economizer position and configuration. Adjust minimum
position.
Check rotation of blower and minimum airflow.
Power off unit and remove high voltage wires. Check resistance
of element, replace if open.
Check using ComfortLink Scrolling Marquee.
Check using ComfortLink Scrolling Marquee.
Check using ComfortLink Scrolling Marquee. Turn Service Test
mode off.
Power off unit. Check contactor and replace if closed.
62
PROBABLE CAUSE
—
REMEDY