What is a High Limit Switch?

There are many parts in your furnace that work together to make it heat your home. One of those parts in your high limit switch. Your high limit switch is a safety mechanism and it is part of your blower assembly. If your high limit is malfunctioning, your furnace may not work correctly or at all. Your high limit has two main functions, one being that it won’t let the fan turn on unless the air in your furnace is warmed to the correct temperature. The other thing it does is kills the burners if the air around the heat exchanger gets too hot to protect the heat exchanger from cracking. If your heat exchanger cracks it could leak out harmful carbon monoxide. You can tell your high limit is malfunctioning if the furnace never stops blowing air. The limit turns of when the air gets cooled to a certain temperature and if it is not shutting off when the air cools, you have a malfunctioning high limit. Your limit switch may cause your furnace to not turn on if your air flow is reduced due to a clogged filter. A clogged filter will restrict air flow and make the furnace work harder than it should so make sure you change the filter every 30 days! You want to make sure to fix any issues you have with your furnace right away to prevent further unnecessary repairs. Bartlett Heating and Air can diagnose and fix all furnace makes and models so call us today for all your HVAC needs!