Honeywell RTH8580WF - Troubleshooting; Glossary

Troubleshooting
If you have difficulty with your thermostat, please try the following suggestions.
Most problems can be corrected quickly and easily.
Display is blank
Check circuit breaker and reset if necessary.
Make sure power switch at heating and cooling system is on.
Make sure furnace door is closed securely.
Make sure C wire is connected (see page 15).
Cannot change system setting to Cool
Check Function 0170: System Type to make sure it is set to match your heating and cooling
equipment (see page 54).
Fan does not turn on when heat is required
Check Function 0180: Heating Fan Control to make sure it is set to match your heating equipment
(see page 55).
“Wait” appears on the screen
Compressor protection feature is engaged. Wait 5 minutes for the system to restart safely,
without damage to the compressor.
Heat pump issues cool air in heat mode, or warm air in cool mode
Check Function 0190: Heat Pump Changeover Valve to make sure it is properly configured for
your system (see page 55).
Button on lower right of screen is blank
This button will remain blank unless the furnace filter change reminder is activated (see page
44).
Red light is on
If thermostat is in Emergency Heat mode the red light is normal. It shows that the thermostat is
in emergency heat mode.
If thermostat is not in Emergency Heat mode, contact a qualified service contractor for repair.
Heating or cooling system does not respond
Press SYSTEM to set system to Heat. Make sure the temperature is set higher than the Inside
temperature.
Press SYSTEM to set system to Cool. Make sure the temperature is set lower than the Inside
temperature.
Check circuit breaker and reset if necessary.
Make sure power switch at heating & cooling system is on.
Make sure furnace door is closed securely.
If “Wait” is displayed, the compressor protection timer is on. Wait 5 minutes for the system to
restart safely, without damaging the compressor (see page 48).
Heating system is running in cool mode
Check Function 0170: System Type to make sure it is set to match your heating and cooling
equipment (see page 54).
Glossary
C wire