Common Furnace Repairs: Limit Switches

Furnace limit switches are an important component of your heating system that help to ensure the safe operation of your furnace. These switches are designed to detect when the temperature inside your furnace gets too high and, in the event of an emergency, they will shut off the furnace to prevent damage or injury.

What causes Limit Switches to fail?

However, like any mechanical device, furnace limit switches can fail over time. There are a few common reasons for limit switch failure:

  1. Dirty or clogged filters: If your furnace filters become clogged with dust and debris, it can restrict airflow and cause the furnace to overheat. This can lead to limit switch failure.
  2. Worn or broken parts: As your furnace ages, certain parts may wear out or break. This can include the limit switch itself, which can cause it to malfunction.
  3. Electrical issues: Limit switches rely on electrical connections to function properly. If there is a problem with the wiring or electrical connections, it can cause the limit switch to fail.

What should you do?

If you suspect that your limit switch may be failing, it is important to call a professional HVAC technician to diagnose and repair the problem. At AAA Heating and Plumbing, we have a team of certified technicians who are experienced in dealing with all types of furnace repairs, including limit switch issues. Our technicians will be able to diagnose the problem and provide a solution that will get your furnace up and running again in no time.


In summary, Limit switches are a critical safety component of furnace, failure of which can be caused by dirty filters, worn or broken parts and electrical issues. If you suspect an issue with your limit switch, it is important to call a professional HVAC technician from AAA Heating and Plumbing to diagnose and repair your furnace.


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