10
TROUBLESHOOTING
Table 4 — Thermostat Troubleshooting
PROBLEM
SOLUTION
Display on thermostat not illuminated
Check for 24 vac at the R terminal connection. Terminal R must be connected
for proper thermostat operation.
‘‘Service Filter’’ is displayed on thermostat
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.
Cooling will not energize
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.
Heating will not energize
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.
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.
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).
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.
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).
When controlling a heat pump, heat comes on
during cooling cycle.
Configure thermostat for heat pump operation (Table 2, Step 4).
When calling for cooling, both heating and
cooling are energized.
The thermostat is configured for a heat pump. Configure the thermostat for non-
heat pump operation (Table 2, Step 4).
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.
The thermostat has been wired incorrectly and the circuit board is burned out.
Thermostat must be replaced.
105
→
Summary of Contents for DEBONAIR 33CS
Page 11: ......
