Why Is There a Blinking Red Light on My Furnace?

Feb 8, 2023 | Heating

If you have noticed a blinking red light on your furnace in Phoenix, AZ, it can indicate a serious problem. For this reason, it’s best to diagnose the issue as soon as possible so the unit can continue providing indoor comfort. In this article, HVAC repair contractor A/C and Refrigeration discusses what a blinking red light on your furnace means and what you can do to troubleshoot it.

Blinking Red Light

What Causes a Blinking Red Light on Furnaces?

A blinking red light on your furnace can indicate various problems, such as:

  • Dirty or clogged air filter 
  • Damaged circuit board or wiring 
  • Faulty thermostat 
  • Poorly functioning blower motor
  • Ignition failure

Troubleshooting Tips

If you’re seeing a blinking red light on your furnace, here are some steps you can take to troubleshoot your unit:

  • Reset the unit. To reset your furnace, turn off the power on the unit and wait at least 10 minutes before turning it back on. This will allow any faulty circuits or components to reset themselves.
  • Check the thermostat. If the reset does not fix the problem, check your thermostat. A malfunctioning thermostat can’t send a signal to the unit, causing a blinking red light. A change of batteries may fix the problem; otherwise, a repair or replacement may be due. Enlist the help of a professional HVAC company as soon as possible.
  • Replace the filters. If the thermostat is still working but the red light is still blinking on your furnace, check its filters. They may already be clogged with too much dirt, which can compromise the unit’s efficiency. It’s a good idea to replace your furnace air filters regularly, preferably at least once every three months.
  • Inspect the circuit board. Another possible cause of a blinking red light is a faulty circuit board. To determine if that’s the issue, consider checking the circuit board for any loose wires or other damage. Have your HVAC technician do it for you to ensure your safety.
  • Check the blower motor. The last step in troubleshooting a blinking red light on your furnace is to inspect the blower motor. A malfunctioning blower motor can cause an airflow problem, resulting in a blinking red light. Since the blower motor is located inside the unit, it would be best to let your HVAC technician inspect it for damage.

Get a Furnace Tune-Up From A/C and Refrigeration

As a homeowner, you should take action when you have a blinking red light on your furnace. Referring to the unit’s manual is a good place to start, and taking the first few troubleshooting steps above can help bring the unit back to its normal operation.

For your HVAC installation and repair needs, get in touch with A/C and Refrigeration in Phoenix, AZ. We can help you establish a routine maintenance schedule for your HVAC system. To learn more, call us at (602) 488-7161, or fill out our online contact form to book an appointment.