Furnace Open High Temperature Limit Switch

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.

Furnace open high temperature limit switch.

Setting the middle arm at this temperature ensures that the fan will switch on at the correct time when the furnace warms ups. A limit switch is a device that s located under your furnace s supply plenum. It also can shut down the furnace burners it if gets too hot inside the furnace identifying a limit switch a typical limit switch consists of a long temperature sensor probe attached to a mounting plate. It reads the temperature of the plenum and waits until it gets appropriately warm.

This video will help you to diagnose and replace a faulty limit control on your gas furnace. 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. The high temperature limit switch senses the temperature of a furnace and tells the blower fan to turn on and off at the appropriate times. 4 4 out of 5 stars 70.

Once the air reaches a preset temperature the limit switch turns on the blower. I have a 1994 lennox 80 mgf series furnace and there is a 4 ligh flashing which say high limit or rollout switch open what does this mean and where can i find the switch and how can it be fixed witho read more. Limit switches turn off the burner and turn on the circulating fan if there is a high temperature condition in the furnace. Set the temperature on the middle component to approximately 105 to 115 degrees fahrenheit.

4 5 out of 5 stars 13. Gas furnace hi limit switch testing using mulitmeter. Step 6 set the arm to left of the middle component to approximately 90 degrees fahrenheit.