The ABC's of Home Heating - High Temperature Limit Switch

The high temperature limit switch (also known as a furnace plenum thermostat) is a safety device on a furnace that is designed to cut the gas supply when the burner temperature exceeds the safe operating range. When the temperature drops back within the safe range, it will allow the gas valve to open again.

The switch commonly operates at an upper limit of 160°F (causing the burner to turn off) and a lower limit of 130°F. The limit switch has two main components: a long temperature sensor located inside the furnace, and a switch mounting plate located on the outside of the furnace.

High Temperature Limit Switch Damage

One of the most common causes of high temperature limit switch failure is improper furnace maintenance, especially dirty air filters. A clogged air filter will reduce air flow, causing heat to buildup in the combustion chamber. This will cause the limit switch to cycle on and off continuously, leading to premature failure.

Have questions about your heating system? Call ABC Plumbing. We're here to help.

Our Blog

VIEW ALL BLOGS

A man standing at his sink, which is surrounded by plants, filling up a black tea kettle.

How to Fix a Blank White Rodgers Thermostat

You might have experienced the worry that comes with discovering your White Rodgers thermostat has gone blank. The good news is that usually, the unit can be brought back to life. In this blog, let's look at some ways to get your blank White Rodgers thermostat operating again.

The Advantages and Disadvantages of Different Water Heater Designs

To help you narrow down the options and hone in on the best new water heater for your Chicago home, here's a useful comparison guide, highlighting the pros and cons of some of the most popular water heater designs.
READ MORE
What Causes Pink Stains on Toilets and Bathtubs?

The blog explains that pink stains commonly found in bathrooms are caused by a bacteria called Serratia marcescens, which thrives in moist environments. When diluted by water, this bacteria produces a red-orange pigment that results in pinkish stains on surfaces like bathtubs, toilets, and showers.
READ MORE
AC Maintenance Guide

The blog talks about the importance of maintaining your AC unit and provides advice on how to maintain older units. It also suggests replacing units when the cost of repairs becomes too high. Finally, it provides information on how to schedule AC maintenance with ABC Plumbing, Sewer, Heating, Cooling & Electric in Chicago and the surrounding areas.
READ MORE