Atwood Furnace Limit Switch Test

It will be located at the top of the panel.

Atwood furnace limit switch test.

The limit switch is a simple temperature controlled switch. At fan limit control settings. How to check limit switches using your voltmeter. To test a limit switch you ll want to check continuity to determine what state the switch is in.

The furnace will not spark unless you have continuity through the sail and limit switch if you have continuity then the circuit board is suspect and can be tested with a special board tester. A limit switch also acts as a safety device for your furnace. Ordered new limit switch atwood 37022 hydro flame limit switch 190 degrees around 15 with shipping paying attention to get one with correct limit temperature and also trying to find out with rv manufacturer for no reason i decided to contact them not atwood whether it s possible to take sail switch out without taking the furnace unit out. It s function is to monitor the combustion chamber heat level.

The fan limit switch temperature settings shown on the dial sketch are discussed separately. If there is a serviceman switch turn it off. If the temperature inside of the plenum gets too hot it shuts off the gas supply to your burners to prevent your. Some furnaces will try a set number of times to start usually three if it fails then it will have to be reset with a power off before it works again.

Remove the cover by lifting it upwards or pulling it off to reveal the body of the switch and two metal arms. Open the access panel and locate the high limit switch. Depending on your furnace model the switch will be surrounded by a silver or white cover. A limit switch is a device that s located under your furnace s supply plenum.

Locate the white limit switch. It reads the temperature of the plenum and waits until it gets appropriately warm. If the gas solenoid is opening up but it is not sparking then the electrode would be suspect as the board sends a signal to the gas solenoid and electrode at the same time. 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.

Before testing the limit switch power off the furnace wait a few seconds and power it back on. If the temperature of the combustion chamber exceeds the preset limit the switch will open and disrupt the flow of current to the circuit board in effect shutting down the main burner.