A limit switch is an important part of most residential furnaces. It controls the blower while also protecting against overheating. The limit switch will perform these tasks automatically; you won’t have to make any manual adjustments to your furnace. If it fails, however, you’ll need to get your furnace serviced by a heating, ventilation, and cooling (HVAC) technician.
What Is a Limit Switch?
Also known as a fan switch or a high-temperature limit switch, a limit switch is a device that controls the blower. It will monitor the temperature of your furnace. Once your furnace has warmed up, it will activate the blower. The blower will then circulate air through your furnace, thereby producing warm air.
Why Your Furnace Needs a Limit Switch
With a limit switch, the blower will only run once your furnace has reached its operating temperature. The blower is a fan that’s connected to the ductwork. It’s responsible for moving conditioned air – heated and cooled air – through your home’s living spaces.
If the blower turns on before your furnace has warmed up, you’ll probably feel cool or room-temperature air coming out of the supply vents. Not only is this uncomfortable, but it can increase your home’s energy costs during the winter.
In addition to controlling the blower, the limit switch will protect your furnace from overheating. It will monitor the temperature of your furnace. If your furnace gets too hot, the limit switch will shut it off.
Signs Your Furnace’s Limit Switch May Be Faulty
Whether you have a gas or electric furnace, it needs a functional limit switch. How do you know if the limit switch is working?
You can feel the air at the supply vents after turning on your furnace. It should feel warm. If the limit switch has failed, it may turn on the blower prematurely, or it may not turn on the blower at all.
An annual furnace inspection will give you peace of mind knowing that the limit switch is working. During an inspection, an HVAC technician will test many of your furnace’s parts, including the limit switch.
If you are experiencing a problem with your air conditioning or heating call us at 512-336-1431 to schedule an appointment. We’ll be glad to come out and take a look at the issue.
1431-183 A/C & Heating proudly serves Round Rock, Georgetown, Cedar Park, Pflugerville, Leander, Liberty Hill, and North Austin.
