If your gas furnace makes a clicking sound at the beginning of the heating cycle, then you have nothing to worry about. But if the noise continues, then it looks like there is something wrong with the furnace.
A clicking sound can be caused by an ignitor that is unable to light (a faulty valve and dirty flame sensor might be to blame). A broken fan blade, worn-out motor bearings, and loose seams in the ducts can also be responsible for the clicking noise.
Why Does My Furnace Make a Clicking Noise?
If you have a gas furnace, a clicking noise can indicate a problem with the ignitor or gas valve. In the worst-case scenario, this can lead to a gas leak; that’s why calling a professional in such a situation is vitally important.
Here are your furnace’s components that might become the reason for the clicking sound:
- The gas valve – if the valve is clogged or broken, it won’t be able to let the gas out. In such a case, the ignitor will continue to click in an attempt to light the system up.
- The thermocouple or flame sensor – these parts, basically, tell the gas valve when to open, if they are dirty or faulty, they will fail to send such a signal, and the ignitor will continue to click.
- The ignitor flame – the flame might be too cold to light the gas.
- Inducer or fan – a broken fan blade might be to blame.
- Motor bearings – once the bearings in the motor become worn, they can start making a clicking sound.
- The ducts – if the sound is coming from the ducts, then it looks like the duct seam has come loose or there is something stuck in the ductwork.
Electric Furnace Clicking Noise
Usually, homeowners that have gas furnaces report hearing a clicking sound. However, electric units can make such a noise as well.
Electric furnaces also have a starter system, but in these units, it is made up of heating elements.
Even though the malfunction of this part of the system will not cause a gas leak, a clicking sound still means that there is something wrong with the furnace and it needs repair.
Is It Normal for a Furnace to Click?
It is normal for a gas furnace to make a ‘click’ whenever it starts off. You will hear this sound when the spark igniter lights the gas a burner.
The ignition system is going to need about a minute to energize. After that, the gas valve will open, the burners will light, and, after a slight delay, the blower is going to turn on to transfer the heat to your rooms.
Why Does My Furnace Click When It Shuts Off?
You might be mistaking a ‘bang’ or a ‘pop’ for a ‘click’. At times, furnaces can make a popping noise, when the system shuts off.
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This happens due to the fact that the metal panels inside the furnace start cooling down and contracting, after being expanded because of the heat.
Furnace Making Clicking Noise No Heat
There might be a few possible causes:
- The flame sensor is shutting the gas off
- The pilot light is dirty, clogged, or worn down
- The ignitor is damaged or clogged or the wiring is loose
- The gas valve is stuck or clogged or there is no gas supply
Furnace Clicking When Off
If you can hear the furnace clicking after the blower motor shuts off, then your heat exchanger might be cracked.
The heat exchanger is the component that prevents the toxic combustion gases from entering the blower.
The components can be making sounds because of the contracting and expanding metal. If there are any cracks, the sound might become louder.
It is extremely important to call a professional to take care of the problem as soon as possible. Otherwise, the heat exchanger might not be able to keep the dangerous gases away from the air you breathe.
Furnace Clicking When Starting
A gas furnace is going to make a clicking sound to initiate the heating process. However, repeated clicking indicates that there is a system failure or malfunction of some sort that needs to be taken care of.
How Do I Stop My Furnace from Clicking?
- Make sure that there is enough gas
First things first, ensure that the furnace is able to get gas by checking if the gas line is operating correctly. If there is a gas supply problem, the rest of your gas appliances are not going to be working, so you can check those.
- Check the gas valve
Sometimes, the gas valve can get stuck because of dirt. You can try gently pushing the component with the other end of a screwdriver.
If the gas valve is still not functioning correctly, then you can check if the part is getting the power that it needs. You are going to need a multimeter for that.
If you do not feel comfortable doing these things or if you have figured out that the valve is not getting any power, then you would have to call a professional.
- Clean the flame sensor
The flame sensor detects the presence of flame in the system. If it is not able to do that, the safety device will shut the system down.
A dirty flame sensor might not be able to detect a flame even if there is one.
Don’t forget to shut off the power to the furnace, before removing the sensor and gently cleaning it with very light grit sandpaper (make sure to scrub only the metal rod).
- Check the ignitor
The ignitor is the thing that keeps the pilot light burning.
If there is not enough airflow from the inducer, the pressure switch had gone bad, or the actual ignitor is not getting any power, then the furnace won’t light.
You can test the ignitor with a multimeter. Also, make sure that there is nothing blocking the flue pipe and that the pressure switch had not gone bad (you can, once again, use a multimeter to confirm that).
- Clean and calibrate the draft inducer fan
If the furnace is clicking but comes on normally, then dirty or loose fan blades might be the issue.
The inducer is located near the heat exchanger. To fully clean the components and check the blades, you would have to remove the fan from the furnace.
- Replace worn-out bearings
Once you remove the draft inducer fan, you can also check the blower bearings. If they seem damaged or worn out, then you would have to replace the bearings.
You can also lubricate the components, if necessary.
- Check the ductwork
Finally, check the ducts for any cracks or bad seems.
Heil Furnace Clicking Noise
A gas Heil furnace can have either a hot surface ignitor that glows to ignite the flame or a spark ignitor.
The clicking sound, in the majority of cases, will be produced by the models with a spark ignition system.
You can try buffing the metal rod of the flame sensor with steel wool and tightening the component’s holder. If that didn’t help, then you might have to get a new flame sensor as the previous one may have been an incorrect choice for this particular furnace model.
Dometic Furnace Clicking Noise
If your furnace comes with a Dometic single-zone thermostat, then it needs to be initialized. This will, most likely, make the clicking sound stop.
Carrier Furnace Clicking Noise
If you hear a very loud clicking noise at the beginning of the heating cycle, it might be an indication of a failing relay or a bad connection.
Can a Furnace Explode?
Yes, furnaces can explode.
That usually happens as a result of ignition and immediate combustion of the gas. As a clicking sound, in a lot of cases, indicates an issue with the ignition system, calling a professional to take care of the problem is extremely important.