How do you reset a limit switch on a furnace?
How do you reset a limit switch on a furnace?
How to Reset a Furnace Limit Switch
- Locate your furnace’s heating duct.
- Locate the white limit switch.
- Look at each arm to identify the settings.
- Identify the component (setting) located in between the two arms.
- Set the temperature on the middle component to approximately 105 to 115 degrees Fahrenheit.
What does open limit device mean on furnace?
In modern furnaces an open limit switch will always bring on the main blower as a safety feature when there is a call for heat but it is not the blower control which usually operates on a timer built in to the. The limit switch will open periodically to prevent over heating.
How do I know if my limit switch is bad?
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.
Why is my limit switch 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 will cause a limit switch to open?
What conditions can cause the limit switch to open during furnace operation?
If the supply air is too hot, the interior of the furnace overheats, which can cause damage to components. The limit switch trips when temperatures are too hot, effectively shutting down the system and locking furnace operation until the unit cools.
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 the limit switch on a gas furnace?
The limit switch on a furnace serves as the primary sensor in the heat exchanger and determines if air within the furnace is warm enough to circulate. The limit switch turns on the blower of the furnace and automatically shuts off when the air temperature exceeds the maximum.
Where is the power switch on a furnace?
It’s usually mounted on the side of the furnace or a wall nearby. The switch allows you or your plumber or repair technician to shut off the electricity to the furnace without having to go to the breaker box and switch off the circuit breaker, among other benefits.
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.
