TROUBLESHOOTING
Table 4 — 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.
Cooling will not energize.
Select COOL mode. Decrease cooling set point to 10 degrees below room tem-
perature. Check for 24 vac at Y1 terminal. If present, thermostat is operating
correctly and problem is with wiring or equipment. If 24 vac is not present, re-
place the thermostat. Check for Compressor Cycle per Hour Limit. Cooling may
be locked out.
Heating will not energize.
Select HEAT mode. Increase heating set point to 10 degrees above room tem-
perature. Check for 24 vac at W1/O/B terminal. If present, thermostat is operat-
ing 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 equip-
ment 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 resis-
tor 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 equip-
ment 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 resis-
tor 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 5).
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 5).
When controlling a commercial heat pump unit,
unit runs in reverse or heating is
always on.
Some commercial heat pumps require that Heat Pump Option on thermostat is
turned OFF. Refer to unit installation instructions for more information.
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