The most common sign of a malfunctioning limit switch is the continuous operation of your furnace’s blower. Just as the limit switch won’t allow the fan to turn on until the warm air has reached the right temperature, the limit switch also shuts down when the air cools to a certain temperature.

Can I bypass a limit switch?

1 Answer. Yes, you can bypass the high limit switch for testing. It’s as trivial to do as it sounds.

How much does it cost to replace a limit switch?

Average Cost of a New Furnace Limit Switch Depending on who your OEM is, this component could roughly cost you anywhere from $4 to $25.

How much does it cost to replace a limit switch on a furnace?

What causes a limit switch to open?

Limit switch codes The limit switch shuts off the burner when the temperature exceeds a preset temperature. When the temperature reduces to normal, the burner will come back on. The most common reason for limits to open is a plugged filter or a dirty blower wheel.

What causes a high limit switch to trip?

A high limit switch will keep tripping due to a dirty flame sensor, short cycling, obstructed airflow, or a defective switch. These lead to overheating within the gas furnace that triggers tripping as a safety measure to prevent fires. Clean and replace dirty and worn-out parts to fix the problem.

What is an open limit switch?

The limit switch is a normally closed switch in series with the sail switch and the thermostat. Being temperature actuated, it is designed to “snap open” when an over temperature condition occurs. Thus the switch is normally opening under full load conditions and that causes arcing of the contacts.

What is a high-temperature limit switch on a furnace?

The high-temperature limit switch is an important device used in forced-air furnaces powered by gas or heating oil. The switch makes sure the furnace is operating safely at its desired settings. It’s also known as a fan limit switch or simply a limit switch What Is a High-Temperature Limit Switch?

Where is the high limit switch on a furnace?

The furnace limit switch is generally found on the furnace just below the plenum. If the plenum reaches too high a temperature, the limit switch shuts it off. It also shuts the blower off once the thermostat indicates that the desired temperature has been reached.

What is a high limit control switch?

High Limit Switch. A high-limit switch is a protective part of a furnace designed to keep the mechanism from overheating itself. A furnace is at a risk of overheating any time airflow is limited from passing through the heat exchanger.