Start at the thermostat...

Ensure that it is set to heat (emerg for heat pumps) and the setpoint is at least five degrees above room temperature. If you have a mechanical thermostat, make sure that it is level and turn the fan switch to on. Is the furnace fan running?

If the fan does not start running...

If the fan is not running, check the fuses or circuit breakers for the furnace and heat pump. If the breaker is tripped or the fuse is blown, then check the wiring in the furnace for signs of damage. Look for scorching and melting of wires as well as connections that have been damaged. Repair any wiring problems then you can reset the breaker or replace the fuse.

If the fan still does not come on, the fan relay, furnace control board, thermostat, blower motor, or control transformer could be the problem.

If the fan starts...

If the fan starts, set the fan back to auto at the thermostat. Wait about one minute, then check to see if warm air is coming out of the vents.

If the air coming out of the vents is cool, the problem could be the heat sequencer, limit control, control board, a bad element, or a wire that is loose or burned off it's connector.

Electric Furnace Troubleshooting, Checking the heat output...

The next step in your electric furnace troubleshooting, is to check the temperature rise across the furnace. You should check the temperature of the air coming out of the closest vent. Also measure the air temperature at the closest return air grille. Find the difference in the two temperatures and compare it to the label on the unit. Most units have a label plate on the inside that gives you a range for the proper temperature rise.

If the temperature rise is less than the recommended minimum, then check to make sure all the elements are operating.

If the temperature rise is higher than the recommended maximum, then check the blower motor for proper operation. If the blower motor is operating properly, then the speed may need to be increased.

After performing the adjustments, you should observe the operation through a complete heating cycle.

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