TROUBLESHOOTINGTable4 — Thermostat Troubleshooting
PROBLEM SOLUTION
Display on thermostat not illuminated. Check for 24 vac at the R terminal connection. TerminalR must
be connected for proper thermostat operation.
‘‘ServiceFilter ’’is displayed on thermostat. Afterthe configured number of blower operating hours, the Service
Filter message will be displayed. This reminds the owner to re-
placethe filter. Reset the Service Filter feature to reset the blower
operation timer to 0 hours.
Cooling will not energize. Select COOLmode. Decrease cooling set point to 10 degrees
belowroom temperature. Check for 24 vac at Y1 terminal. If present,
thermostatis operating correctly and problem is with wiring or equip-
ment. 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. SelectHEAT mode. Increase heating set point to 10 degrees above
roomtemperature. Check for 24 vac at W1/O/B terminal. If present,
thermostatis operating correctly and problem is with wiring or equip-
ment. If 24 vac is not present, replace the thermostat.
Whenusing 4 wires (R,G,W,Y), the cooling equip-
menttries repeatedly to turn on, but cannot. At
times the display dims or disappears.
Thereis not enough power available. Connect a 270 ohm, 10 watt
powerresistor at the air-conditioning equipment between terminals
W and C (non-heat pump applications only).
Whenusing 4 wires (R,G,W,Y), the heating equip-
menttries repeatedly to turn on, but cannot. At
times the display dims or disappears.
Thereis not enough power available. Connect a 270 ohm, 10 watt
powerresistor 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 (Table2, Step 3).
Whencalling for cooling, both heating and cool-
ing are energized. The thermostat is configured for a heat pump. Configure the
thermostat for non-heat pump operation (Table2, Step 3).
Whencontrolling a commercial heat pump unit,
unit runs in reverse or heating is always on. Commercial heat pumps require that Heat Pump Option on
thermostat is turned OFF.
Copyright1998 Bryant Heating & Cooling Systems CATALOGNO. 809-683