A fan limit switch is a critical component of the furnace that keeps your house warm on cold nights. It is a component that tells the blower assembly to turn on and start blowing warm air up your ducts and throughout your home. The furnace limit switch, also known as the high limit switch, controls the turning-off timing of the blower assembly. The turning off may be necessary due to overheating or your house reaching a higher temperature.
What Does A Furnace Fan Limit Switch Look Like?
While it varies significantly from one furnace manufacturer to the next, you may find the high limit switch by removing the furnace cabinet lid. According to the heating repair magnolia experts, the fan limit switch is mounted on a plate. It includes a long temperature sensor extending into the furnace plenum, an air chamber filled with the air from the blower fan. A wire travels from the scale to the blower and another to the gas valve.
How Does A Furnace Fan Limit Switch Work?
When your furnace’s thermostat detects that your home’s temperature is too low, it signals the burners to ignite and heat the air in the plenum. When the plenum air becomes sufficiently hot, the fan limit switch instructs the blower assembly to blast heated air through the heat exchanger. According to the heating service magnolia experts, using the air duct system, the warm air should move throughout the home. When the thermostat determines that your house is adequately warm, it turns off the furnace. The blower will continue to operate until the internal furnace temperature reaches a safe level.
If your furnace’s burner continues to operate even when the system as a whole fails or breaks, the high limit switch will cut off the gas valve to avoid a fire or other hazard.
What Is The Procedure For Replacing A Furnace Fan Limit Switch?
Follow these instructions to repair your furnace’s damaged or worn-out furnace limit switch and save yourself the bills arising from hiring other local professionals of the heating service magnolia.
- 1. Deactivation of the Furnace: Turn off the electricity to your furnace through the service switch or circuit breaker. It will help you avoid any accidents during the DIY replacement.
- 2. Deletion and Configuration: After turning off the furnace, remove the old high-limit switch from the furnace cabinet. Install the new button by wiring it just like the old one. It is commonly accomplished with just two screws, wires, and terminals. Follow its directions to ensure that the dial settings are the same as before or alter it as required.
If the model seems older, check the installation instructions if you need assistance with the minor extra tasks, such as connecting the third line, snapping on a tab switch, and tweaking dial settings to read the same as the previous one. Otherwise, you can always contact Fenwick Home Services to ensure that everything is done correctly.
- 3. Operational Evaluation: Turn on the furnace and adjust the thermostat to indicate the start of the heating process once you’ve set the new furnace limit switch. Check if the vent is pushing out enough warm air and that nothing seems to be out of the norm to validate your successful switch repair.