Troubleshooting - Carrier Debonair 33CS Installation, Start-Up, And Operating Instructions Manual

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PROBLEM
Display on thermostat not illuminated
''Service Filter'' is displayed on thermostat
Cooling will not energize
Heating will not energize
When using 4 wires (R,G,W,Y), the cooling
equipment tries repeatedly to turn on, but
cannot. At times the display dims or disappears.
When using 4 wires (R,G,W,Y), the heating
equipment tries repeatedly to turn on, but
cannot. At times the display dims or disappears.
When controlling a heat pump, heat comes on
during cooling cycle.
When calling for cooling, both heating and
cooling are energized.
The thermostat temperature display rises to 99 F. There is not enough voltage to the thermostat. Check wiring and power supply.
The resistor labeled "L3" on the thermostat is
burned out and brown. Thermostat will not work.
105

TROUBLESHOOTING

Table 4 — Thermostat Troubleshooting
Check for 24 vac at the R terminal connection. Terminal R must be connected
for proper thermostat operation.
After the configured number of blower operating hours, the Service Filter mes-
sage will be displayed. This reminds the owner to replace the filter. Reset the
Service Filter feature to reset the blower operation timer to 0 hours.
Select Cooling mode. Decrease cooling set point to 10 degrees below room
temperature. Check for 24 vac at Y1 terminal with a load connected. If present,
thermostat is operating correctly and problem is with wiring or equipment. If
24 vac is not present, replace the thermostat. Check for Compressor Cycle per
Hour Limit. Cooling may be locked out.
Select Heating mode. Increase heating set point to 10 degrees above room tem-
perature. Check for 24 vac at W1-O-B terminal with a load connected. If present,
thermostat is operating correctly and problem is with wiring or equipment. If
24 vac is not present, replace the thermostat.
There is not enough power available. Connect a 270 ohm, 10 watt power resistor
(supplied with thermostat) at the air conditioning equipment between terminals
W and C (non-heat pump applications only).
There is not enough power available. Connect a 270 ohm, 10 watt power resistor
(supplied with thermostat) at the air-conditioning equipment between terminals
Y and C (non-heat pump applications only).
Configure thermostat for heat pump operation (Table 2, Step 4).
The thermostat is configured for a heat pump. Configure the thermostat for non-
heat pump operation (Table 2, Step 4).
The thermostat has been wired incorrectly and the circuit board is burned out.
Thermostat must be replaced.
10
SOLUTION