How to Troubleshoot a Heat Pump Thermostat With the Emergency Light Blinking

Troubleshooting the emergency blinking light on your thermostat solves the lock-out problem.

Many thermostats include an emergency heat light that flashes continuously when the unit is locked out, a feature that causes your unit to shut itself down and sends signals to your thermostat letting you know there's a problem with certain parts of your unit. Troubleshooting these emergency blinking problems can improve your unit's performance.

1. Count the number of flashes. Some units flash a code that allows you to determine the problem with your unit. The number of flashes are between two and nine. Refer to your manual for the troubleshooting steps associated with the code.

2. Turn off your thermostat. Wait about 30 seconds and then turn it back on. This restarts your thermostat. In some cases, your system may restart after about 10 minutes.

3. Turn off the power on your indoor unit for five minutes and then turn it back on if the emergency light on your thermostat continues to blink. Your unit will lock-out (shut down) during inclement weather, so turning off the power and then turning it back on may solve the blinking problem.

4. Inspect the outdoor unit after 10 minutes to see if it's running. If the light on your thermostat doesn't go out, open the electrical panel located next to your outdoor unit and turn off the circuit breakers. Wait a few minutes and then turn them back on. This should reset them. Refer to your unit's manual if you're unsure where the circuit breakers are located.

Tip

Contact a qualified appliance technician if your unit continues to lock-out.