If the furnace does not have backup heat, controls are minimal, consisting of a thermostat, relay and fan. Most furnaces with backup heat will have a second thermostat to control the auxiliary heat.
If the furnace has backup heat that will not operate, try the following:
- Make sure that the thermostat is set higher than the actual room temperature. If there is central air, set the selector switch to heat. If the thermostat is programmable, make sure it has fresh batteries.
- Check for power at the furnace by turning up the wood thermostat and seeing if the draft motor runs.
- If the backup is oil, reset the red button on the burner once. Repeated resetting can cause an explosive condition. If the burner will not run, call a serviceman.
- If the backup is gas check the pilot light, or watch for ignition when the unit first tries to start up.
- If the backup is electric, extreme caution must be taken if accessing the controls. Deadly high voltage exists behind some service panels.