What are Furnace Limit Switches, and Why are They Important?

If you’re like most homeowners, you probably don’t think about your furnace all that often. But when it comes time to turn on the heat, and you realize your furnace isn’t working, suddenly, it becomes a top priority! One of the most important components of your furnace is the limit switch. This article will explain what a limit switch is and why it’s so important.

Why are furnace limit switches important, and what do they do?

Essentially, furnace limit switches are responsible for turning on the furnace blower and regulating the desired heat inside the furnace. Without a functioning limit switch, your thermostat would not be able to tell when the desired temperature has been reached. In other words, it is an essential component of controlling your home’s heating system! A furnace limit switch typically consists of an exterior plate and a temperature probe inside the furnace housing.

The probe is usually connected to the thermostat, which monitors your home’s temperatures and sends out signals to activate when heating or cooling is needed. For example, when the room reaches the desired temperature, the probe will tell the switch to turn off, thus stopping further heating or cooling. Apart from that, it will also benefit if you know what does the hold button on a thermostat means, as it is also a very important mechanism that helps in regulating the temperature of your home.

How to Know If your Furnace Limit Switch Is Broken?

If your furnace limit switch is broken or not working correctly, it can cause a variety of issues. One of the most common signs that you have a faulty limit switch is if your furnace won’t turn on at all or only turns on briefly before shutting off again. Other signs include the blower continuing to run even when the desired temperature has been reached or if the furnace never reaches its desired temperature.

In any case, it’s important to have a professional HVAC technician for furnace maintenance in Palatine to diagnose and repair any issues with your furnace as soon as possible. Doing so can help protect your home from further damage and costly repairs down the line.


That’s all you need to know about furnace limit switches, why they are important, and how to spot when yours is broken. Remember, being proactive with maintenance and repairs is key in ensuring your furnace remains in good shape throughout the years. If you have any questions or concerns about your furnace limit switch, be sure to contact a qualified HVAC technician right away.