Why is my furnace turning on but not igniting?

If your gas furnace initiates the start cycle but does not fire up, it’s likely because of a faulty, damaged, or dirty ignitor/sensor. This is a very common furnace problem—you can try to clean the sensor and replace the ignitor.

How do you diagnose a bad furnace ignitor?

Here are a few indications that you have a faulty ignitor.

  1. No Cold Air.
  2. The Furnace Won’t Come On.
  3. The Furnace Suddenly Stops Blowing.
  4. Starts, Then Stops, Then Starts Again.
  5. Tripping the Breaker More Than Once.
  6. I Hear the Click, But Nothing Happens.
  7. Flame Sensor Problems.
  8. Short Circuit.

How do you reset a furnace ignitor?

Resetting The Ignitor You can reset the ignition on your furnace simply. To do this you must cut the power to the furnace first by turning off the circuit that powers it. Once the power is off you can remove the burner door to reveal the ignitor. Turn this to “off” and leave it off for at least 5 minutes.

Where is furnace flame sensor?

burner assembly
A furnace flame sensor is a very basic part of your furnace. It’s located on the burner assembly and is just a thin metallic rod. It’s usually bent, and it sits just in front of the pilot flame inside the furnace.

Do all gas furnaces have a flame sensor?

Not every furnace has a flame sensor. If your furnace has a spark ignitor and not a flame sensor rod, then that ignitor is acting as a sensor. HOW IT WORKS: The control board sends electricity to the flame sensor.

Can Hear furnace but no heat?

When you turn the furnace on but no heat comes out, there may be an obstruction. Dirty air filters restrict airflow, which can make it feel like not much heated air is coming out of your vents. Check the furnace filter and replace it if its surface is covered with contaminants.

Why is my gas furnace not lighting?

If your furnace won’t ignite, the source of the issue may be a broken flame sensor. The sensor is responsible for turning off the gas burners to avoid gas buildup. Once this component starts to malfunction, it may stop the burners from igniting altogether.

How do I clean my furnace flame sensor?

The Process of Cleaning a Furnace Flame Sensor

  1. Turn off the furnace power.
  2. Turn off the gas valve.
  3. Remove the furnace flame sensor.
  4. Clean the sensor with an emery cloth.
  5. Return the flame sensor.
  6. Restart the furnace.

What do flame sensors look like?

The flame sensor on your furnace is an important but simple part. It will look like a thin metallic rod and is set in front of the pilot flame on the interior of your furnace. Both of these parts can be located inside of the burner assembly of your furnace which is typically in the bottom of your furnace.