Furnace Produces No Heat
- Circuit breaker tripped or fuse is blown.
- Thermostat components dirty.
- Loose wires or open connection.
- Bad battery on digital electronic thermostats.
- Reset circuit breaker or replace fuse.
- Remove thermostat cover and gently clean components especially the bimetallic coil and the switch contact surfaces if the thermostat does not have a mercury switch.
- Set the thermostat to its lowest setting and clean the bimetallic coil with a soft brush or compressed air. Set the thermostat to its highest setting and clean the coil again. Reset the thermostat to its desired setting.
- Tighten any loose screw terminals. If a wire is loose from its terminal, place wire back on terminal clamp and tighten screw.
- Check for loose connection or disconnected wire on low-voltage transformer usually mounted on furnace
- On electronic models, check to see if the display is working indicating power. If it is not working, replace the batteries in the electronic thermostat.