Furnace Clicks but Doesn’t Turn On – Troubleshooting Guide

A lot of different things inside your furnace can cause the unit to click. However, there are two main issues that will make the furnace produce this noise and not turn on.

Your heating unit is experiencing issues with the ignition or the blower. The furnace will click and not ignite, in case there is a problem with the gas line, thermostat, burners, or flame senor; the blower won’t start if the bearings are worn out or the capacitor is faulty.

Why Is My Furnace Clicking but Not Igniting?

The chances are high that your furnace is making a clicking sound because the spark ignitor is trying to ignite the pilot light or burners.

A faulty ignitor or pilot light might be the root cause of the problem. The elements could also simply be dirty.

A few other reasons for ignition issues include:

  • Problems with the gas line (a blocked gas line, a faulty gas valve, gas leaks, etc.)
  • A defective thermostat or improper thermostat settings
  • A clogged filter
  • A broken flame sensor
  • Dirty burners

Read: Is It Ok To Have A Furnace In The Crawl Space?

Furnace Clicks but Doesn’t Turn On

Issues with the ignition are not the only thing that will stop the furnace from turning on. The unit won’t be able to function if the blower doesn’t start.

This will happen if:

  • The bearings in the inducer motor have worn out
  • The fan shafts are clogged
  • The blower motor had failed
  • The capacitor had gone bad
  • The vents are clogged
  • There is a blown fuse

Oil Furnace Clicks but Doesn’t Turn On

When an oil furnace is clicking, it’s either a fuel delivery problem or there is an issue with the motor.

If your unit has a red reset button on the actual motor, you can try pushing it once the motor cools down – this might fix the issue.

Read: How To Choose Furnace Filter?

Why Is My Furnace Just Clicking?

There are quite a few different parts in a furnace that can cause the clicking sound:

  • A broken or clogged gas valve won’t let any gas out and this, in its turn, will make the ignitor continuously click
  • A faulty or dirty flame sensor or thermocouple won’t be able to sense the flame and won’t tell the gas valve to open
  • An issue with the ignitor flame – it can be too cold to burn the oil or gas, that’s why the ignitor will continue to click
  • The fan or inducer can make a clicking sound if they have a broken fan blade
  • If you have an electric furnace, the clicking noise can be coming from one of the electrical components
  • Finally, your ducts can produce a clicking sound, if a seam had come loose or if there is something trapped in the system

Furnace Clicking Sound After Turning Off

The component that can be making a clicking noise in a furnace that has been turned off is the ductwork

The heated air will still be traveling through the system of ducts, even when the unit shuts down. If the ducts have come loose, then they could be producing a clicking noise.

Read: Why Furnace Not Responding To Thermostat?

Furnace Clicking While Running

If the furnace is clicking but the heat is working normally, then the chances are high that it’s the ductwork causing this noise.

A dirty or rusted shaft fan shaft that needs lubrication and worn-out bearings on the main blower can be making a clicking sound. If you have an oil furnace, then the noise might be coming from the inducer fan. 

Carrier Furnace Clicking Noise

The clicking sound might be an indication of a failing relay or a bad connection. In an electric furnace, the noise can mean that the heat exchanger had developed a crack.

In any case, calling an HVAC expert is advised.

Is a Clicking Furnace Dangerous?

Remember that it’s absolutely normal for your furnace to make a clicking sound as soon as it starts (it’s the sound of your ignition starting). However, if the unit continues clicking, then there might be something wrong.

It looks like the spark ignitor is trying to light the burner. Such a situation might lead to a gas leak if the unit’s gas valve continues to stay open.

A clicking sound can be caused by a wide range of different malfunctions and even though the majority of them can’t be considered life-threatening – you should definitely take care of the cause of the sound as soon as possible.

Read: Why Furnace Stops Working At Night?

Can Furnaces Explode?

It is highly unlikely for a furnace to explode as modern units are built to high safety standards and will simply shut off, in case of any emergency.

With that being said, it is possible for a gas furnace to catch fire and explode. This might happen, if there is a fire in the house, or if gas has been building up in the unit.

Gas furnaces can also leak combustion gases if there is a crack in the heat exchanger.

When it comes to electric furnaces, in theory, the units might explode if you supply them with more energy than low voltage without a transformer upgrade.

How Do I Know If My Furnace Is Going to Explode?

  • The carbon monoxide detector had gone off
  • You smell gas, burning plastic, or smoke
  • The furnace is getting extremely hot
  • The color of the pilot light has changed from blue to yellow
  • The furnace is making unusual noises (like a high-pitched squeal, for example)

How Do You Fix a Furnace That Clicks?

If your furnace is clicking and there is heat, then you can try cleaning and lubricating the fan shaft, replacing the motor bearings (if they are worn out), cleaning the blades of the inducer fan and tightening them up, if any of them are loose.

If the furnace is making a clicking noise and is not working, then:

  1. Inspect the pilot.
  2. Replace it, if necessary.
  3. Check gas flow.

It is advised to call an HVAC professional for any other tasks.

Read: Does Furnace Reduce Humidity?

Why Is My Furnace Not Starting?

  1. Check the circuit breaker
  2. Check the thermostat settings
  3. Make sure that the air filters are clean
  4. Check the pilot light
  5. Inspect the blower motor and the ignition switch

Furnace Turns on but No Heat

Thermostat settings, airflow issues, and problems with the fuel supply or the ignition system might be to blame. 

Furnace Not Kicking on When Temp Drops

The chances are high that it’s your thermostat that is causing the problem. Make sure that it is switched to ‘heat’ and that the temperature that you have set on the device is lower than your house’s temperature.

Issues with the power supply, the blower, and the pilot light can also stop the furnace from turning on, as well as a full condensate pan.

How Do I Know If My Furnace Spark Ignitor Is Bad?

Here are the tell-tale signs of a faulty spark ignitor:

  • The furnace won’t run
  • The unit keeps tripping the breaker
  • The furnace turns on and then suddenly stops running

How Do I Clean My Furnace Ignitor?

You’ll usually find the ignitor under the access panel, mounted on the wall next to the first burner (the one closest to the gas valve).

You can try cleaning the ignitor with compressed air or by gently rubbing the element with fine steel wool. Don’t forget to switch the power to the furnace off before performing any manipulations.

How Much Does It Cost to Replace Furnace Ignitor?

The actual ignitor costs around $30-$50. If you’ll be inviting a professional to replace the element, be prepared to pay up to $425 for the labor and component.

How Often Should Furnace Ignitor Be Replaced?

A furnace ignitor is one of the elements that is subjected to extreme heat. This component won’t last as long as the heat exchanger, for example, and should be replaced every 3-7 years.