The limit control switch is a mechanism designed to stop the furnace from overheating. A faulty limit control may shut the furnace down immediately when it attempts to come on. Or it may fail to turn the furnace off in case of overheating. Usually, fixing this requires replacing the limit control switch.
What does a limit switch do in a electric furnace?
The furnace fan limit switch is designed to activate and deactivate the furnace blower assembly. This component is responsible for transmitting warm air throughout the air ducts in your home. In addition, the furnace limit switch is also engineered to shut down the furnace to ensure it doesn’t overheat.
Where is the limit switch on electric furnace?
A typical limit switch consists of a long temperature sensor probe attached to a mounting plate. The probe extends through the wall of the furnace, and the plate fastens to the outside of the furnace’s hot air supply plenum, above the combustion chamber or heat exchanger.
What would cause an electric furnace not to kick on?
2. Your Furnace Produces Little to No Heat. If your electric furnace is running but doesn’t seem to be producing enough heat, it could be caused by the thermostat being on the wrong setting, a clogged filter, dirty air ducts, or a major issue with the furnace.
How do I know if my limit switch is bad?
The switch should be immediately suspect if the voltage drop is 0.2 VDC or higher (Fig. 1 indicates a bad limit switch). Verify that your ohmmeter will read “0” when the two leads are shorted together. The meter should read between “0” and “0.1” Ohms.
How do I know if my high 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.
Can you 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.
Can you reset a limit switch?
The function of your furnace limit switch is to tell the fan when to turn off and on depending on the temperature in the home. … However, for your own safety, don’t attempt to reset the switch without first consulting your furnace’s instruction manual.
How much does a limit switch for a furnace cost?
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.
Can an electric furnace overheat?
Failure of mechanical components in your system can cause your furnace to overheat. Electrical wiring and the fan blower in your furnace are subjected to a great deal of stress. Your furnace could overheat due to a short circuit or inadequate circulation.
How do you jump a limit switch?
If you locate the limit switch there are two wires going to it. Disconnect power or turn the power off at the circuit breaker. Take the two wires and remove the wires from the limit switch. Tape the two terminals together thus, jumping the limit switch and bypassing it for testing.
Why is my furnace going off on high limit?
A high-limit switch will turn a furnace off if it becomes too hot or is obstructed. Changing the furnace’s air filter and cleaning the blower motor may help the switch perform better.
What can go wrong with electric heat?
Electric troubles are responsible for most heating system failures, and this includes gas furnaces and heat pumps as well. Loose or corroding wiring and broken relays are among the more common troubles that can cause problems for an electric furnace.
Can a electric furnace catch on fire?
An electric furnace doesn’t pose any danger of toxic gas leaks the way a natural gas furnace might. However, electric furnaces are powerful electronic devices and can potentially start fires. Fortunately, this problem is easy to avoid if you take some basic steps.