Gas Furnace Limit Switch Open

The burners will then light.

Gas furnace limit switch open.

If the furnace failure code indicates an open limit or open high temperature switch or open rollout switch it is probable that the furnace has overheated. Remove the cover by lifting it upwards or pulling it off to reveal the body of the switch and two metal arms. Through the little glass viewing window i see red and green flashing lights. When i open the cover to the furnace and the safety switch resets as it should when i close it.

The panel inside says the 4 flashing red means an open limit switch. A typical limit switch consists of a long temperature sensor probe attached to a mounting plate. My 8 year old trane model tuh2d120a9v5va furnace is not giving out heat. Details about setting the temperature controls on a fan limit switch are.

It will be located at the top of the panel. Once the plenum reaches a specific temperature the limit switch sends a signal to the air handler to begin running and delivering warm air to your home. My blower is running constant. The red flashes 4 times the green 3 times and these overlap.

Depending on your furnace model the switch will be surrounded by a silver or white cover. Locate the white limit switch. By keeping the fan off until the supply air plenum is warm the heating furnace limit switch prevents the furnace blower from sending chilly air into the building if the oil or gas burner has not sufficiently heated up the furnace heat exchanger and supply air plenum. The probe extends through the wall of the furnace and the plate fastens to the outside of the furnace s hot air supply plenum above the combustion chamber or heat exchanger.

The thermostat seems to work normally the filter was real dirty and i replaced it. A limit switch is a device that s located under your furnace s supply plenum. 12 thoughts on test and replace the fan limit switch on a furnace ken november 22 2020. The service people are all busy due to the recent storms.