How do I know if my high limit switch is bad?

How do I know if my high limit switch is bad?

One of the most common issues that happens when a high limit switch goes bad is that it fails to signal the blower fan to turn off. If your fan keeps running continuously (and you’ve checked that your thermostat is set to AUTO rather than ON), that could be a sign of a bad high limit switch.

How do I know if my furnace fan 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 furnace fan not turning on?

Start by turning the furnace off, turn your thermostat to “fan only,” and wait a few minutes. If you see or hear the fan turn on, your blower motor is not the culprit. If the fan does not start, you have a wiring issue (circuit breaker trips) or motor problem (circuit breaker does not trip).

Where is my furnace fan limit switch?

Your fan limit switch is located inside the furnace panel cover, usually near the upper right corner. The fan limit switch is responsible for turning the blower on and off at the appropriate times.

How do you reset a high limit switch on a furnace?

How to Reset a Furnace Limit Switch

  1. Locate your furnace’s heating duct.
  2. Locate the white limit switch.
  3. Look at each arm to identify the settings.
  4. Identify the component (setting) located in between the two arms.
  5. Set the temperature on the middle component to approximately 105 to 115 degrees Fahrenheit.

Why does my furnace high limit switch keep tripping?

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.

Why do limit switches go bad?

When your furnace doesn’t have proper airflow, like when it is operating with a dirty filter, your heat exchanger will repeatedly overheat and put your limit switch through excess wear and tear. This can eventually cause it to malfunction.

How do you reset a furnace fan?

How to Find and Reset your Furnace Motor Blower

  1. Step 1: Turn off the power to the furnace.
  2. Step 2: Remove the blower compartment cover.
  3. Step 3: Make sure the blower is completely cooled off.
  4. Step 4: Locate the reset button.
  5. Step 5: Press the button in (assuming that this is your issue and that the button has popped).

Why is my fan motor not working?

One of the most common reasons fans stop spinning is because of a dead capacitor. Each air conditioning system has several capacitors, including the start capacitor, which sends signals to the motor, and the run capacitor, which keeps the motor running. Capacitors can go bad over time and need to be replaced.

Where is the reset button on a limit switch?

The High Limit Reset Button is located behind the gas valve. 3. Reach your hand on top of the box labeled high limit reset button to feel for the red button.

How does a Sunbeam octopus furnace work?

In 1941 however, a brand new American Standard/Sunbeam Octopus Furnace was installed to provide central heating. The octopus furnace was a coal burning gravity hot air type. A gravity furnace heats the air and the hot air slowly rises through a duct system as hot air always rises.

What does open limit switch mean on a furnace?

Limit switch codes. If the furnace failure code indicates an “open limit” or “open high temperature switch” or “open rollout switch”, it is probable that the furnace has overheated. Limit switches turn off the burner and turn on the circulating fan if there is a high temperature condition in the furnace.

What happened to the old octopus furnace ducts?

Old octopus furnace ducts removed during asbestos remediation. The first step was removing asbestos. All my asbestos ducts had been safely encapsulated with paint making them appear like new. They were removed from the old octopus furnace and new duct work was installed on the new furnace.

What does open rollover switch mean on a furnace?

If the furnace failure code indicates an “open limit” or “open high temperature switch” or “open rollout switch”, it is probable that the furnace has overheated. Limit switches turn off the burner and turn on the circulating fan if there is a high temperature condition in the furnace.