At what temperature does the high limit switch open?
160°F
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.
What causes a high limit switch to trip on a furnace?
If the air inside your furnace gets too hot, the limit switch trips to prevent overheating. If the furnace high limit switch trips due to overheating, there is likely an airflow issue that is preventing proper air movement through the system. A dirty filter is the most common cause of airflow issues.
Can you bypass furnace high limit switch?
When testing if a switch is good or bad, it can be bypassed for a short time. The furnace should Not be run for an extended time with the jumper as the limit switch is a necessary safety feature.
What causes limit switches to go bad?
Over time, your furnace’s limit switch can develop problems. When your furnace doesn’t have proper airflow, like when it is operating with a dirty filter, your heat exchanger will repeatedly overheat and put your limit switch through excess wear and tear. This can eventually cause it to malfunction.
How does a fan limit switch work?
To put it very simply, the furnace fan limit switch is a control that tells your furnace’s fan when to turn on and off. So, when the furnace isn’t on, it tells the blower not to operate (and send cold air into your home) and when the furnace is on, it tells the blower to turn on and start circulating the warm air.
What is a high temperature limit switch on a furnace?
A high-temperature limit switch also called a fan limit switch or simply a limit switch is an important device used in forced-air furnaces powered by gas or heating oil. Simply put, it senses the temperature of the furnace and tells the blower fan to turn on and off at the appropriate times.
What is a high temperature hermetically sealed switch?
HR Series high temperature hermetically sealed switch is sealed as defined in MIL-PRF-8805, Symbol 5. The HR Series combines maximum sealing, high temperature [315 deg C (600 deg F)] capabilities and rugged, heavy duty, corrosion-resistant
What is the temperature range of an EGM HR switch?
The HR Series combines maximum sealing, high temperature [315 deg C (600 deg F)] capabilities and rugged, heavy duty, corrosion-resistant Description: EGM Single Hole Fixing Limit Switches are technically sophisticated control switches that have held up for decades in harsh industrial applications and are entirely maintenance free.
What is a limit switch on a thermostat?
When the house temperature reaches the designated setting on the thermostat, the burners turn off, but the limit switch keeps the blower running for a little while to extract as much heat as possible from the heat exchanger.