Furnace High Limit Switch

If the blower came on at the same time as the burner it would pump cold air through the house at first.

Furnace high limit switch.

Depending on your furnace model the switch will be surrounded by a silver or white cover. They will be mounted near where the flame may rollout the front of the furnace due to venting blockages heat. As a safety the high limit. The blower will continue to run until either the system is reset or the limit switch closes.

A limit switch is a device that s located under your furnace s supply plenum. Remove the cover by lifting it upwards or pulling it off to reveal the body of the switch and two metal arms. Turning the fan motor on and off is the high limit switch s main job. The high limit switch in your gas furnace is a small part with two very important jobs.

When the high limit switch trips the flame heating element will be shut off and the blower will continue to run to clear the heat. The switch makes sure the furnace is operating safely and at its desired settings. It reads the temperature of the plenum and waits until it gets appropriately warm. Note that the limit switch has nothing to do with the thermostat.

In this episode of repair and replace vance shows how to replace the high limit switch in a gas furnace. The high limit switch shuts down the furnace at a set limit so a clog doesn t burn out the system. The high temperature limit switch is an important device used in forced air furnaces powered by gas or heating oil. The limit switch includes a sensor in the heat exchanger to.

Rollout switches and high temperature fuses are different from limit switches in that when they open they will not close again unless reset as in the case of the rollout switch or replaced as in the case of the high temperature fuse. This is the role it plays in every cycle of your furnace s normal operation. 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. If the high limit switch was bad the furnace should not fire.

It will be located at the top of the panel. A pair of wires is connected to the switch. High limit switch a high limit control switch will turn off the gas to a furnace if the temperature becomes too high. For example if the blower motor stopped running then no air would move through the unit.

The limit switch is a safety switch that monitors t. I believe high limit switches are normally closed and. Rather it is wired in series with the 24 volt control circuit of your furnace. It s also known as a fan limit switch or simply a limit switch.

The flames would raise the temperature inside the unit and have no place to go getting hotter and hotter.