Why does my central heating make a tapping sound?

Author: Deonte Blanda  |  Last update: Wednesday, December 3, 2025

Whistling and tapping noises are common symptoms of internal mineral deposits as water struggles to flow through narrowed pipework. Similarly to air trapped in the system, you may also experience radiators that are hot at the top but cold at the bottom.

Why does my central heating make a tapping noise?

As the pipes expand, they may be able to brush against other surfaces, like walls, joists, brackets and floorboards, causing a creaking, groaning or gurgling noise. If there is air running through the pipes and radiators as well as water, it can create a tapping or clicking noise.

Why is my heater making a tapping noise?

A worn-out igniter can periodically fail, and if it keeps trying to light the gas, your furnace will make a clicking sound. The noise may last until the flame ignites or the gas valve closes. This failure and its corresponding clicking noise can also result from the igniter's wiring coming undone.

How to stop central heating from knocking?

If the pipe is secure and simply close to a wall, joist or other pipe, consider putting a small amount of cloth, foam or felt between the wall and pipe to remove the vibration. For pipes that have come loose, it can be much more difficult, especially if they're beneath the floorboards.

Why does my heating unit make a knocking sound?

Inside your air ducts, two processes occur—contraction and expansion. As temperatures rise, your air ducts' metal parts heat up. These parts will then move around, producing a knocking sound in furnace vents. Fortunately, this is entirely normal and generally doesn't signal an issue.

How to fix clicking, ticking and noisy pipework. How to quiet heating pipes.

How do I stop my heater from knocking?

Bleeding your radiators will release any air that may be trapped inside. When air gets into your heating system, it can cause a banging noise because it increases the pressure in the system. Releasing pressure by bleeding the pipes of excess air can stop the banging noise from occurring.

Why is my AC making a tapping sound?

There are a few common reasons an air conditioning system may make a clicking noise, including loose parts in the compressor, electrical issues, thermostat problems, or an issue with the fan unit.

How to stop a water hammer in central heating?

This can be fixed by retrofitting a water hammer arrestor. The arrestor acts like a mini expansion vessel and gives the pressurised water somewhere to go, thereby reducing the pressure. Lower pressure equals less hammer-like noise!

Why is my wall heater making a knocking noise?

Knocking

A knocking noise could also mean there's an issue with the blower fan. For example, if the fan becomes misaligned, the blades may hit against parts of the furnace. As mentioned earlier, a loose fan may cause a scraping sound as well.

How often do you need to bleed radiators?

You should bleed your radiators at least once a year, typically before winter arrives in order to ensure the efficiency of your heating system. Regularly checking for trapped air also helps to make sure that your system operates effectively and reduces energy consumption.

How do I stop my heater from ticking?

Turn the heat up and listen to where sounds are coming from to identify where the issue is. You may find areas where pipes are touching walls or other items that cause noise. The easiest fix is to shorten the pipe. Cut the pipe and pull it gently away from the wall until it has 1 inch clearance.

How do I stop my radiator from tapping noise?

SOLUTION: The first thing to do is to bleed the air from the radiator, which will require the key that accompanies the heating system. Not to worry if the key is lost, check out our tips on how to bleed a radiator, and how to bleed a radiator without a key.

Why is my heating vent making a clicking sound?

If the furnace is running normally but there's a clicking sound coming from the ductwork or air vents, there might be a cracked or loose duct. You can have a technician check for this the next time you call them for duct cleaning. Damaged ductwork should be replaced immediately.

Why does my heat make a tapping noise?

However, the build up inside your heating system is invisible until it starts to cause problems. Whistling and tapping noises are common symptoms of internal mineral deposits as water struggles to flow through narrowed pipework.

How do I stop my pipes from tapping?

How To Stop Water Hammer
  1. Are air pockets the problem? Another issue that can cause a similar banging sound is air pockets in your pipes. ...
  2. Close valves half-way. ...
  3. Replace intake connections. ...
  4. Install water hammer arrestors. ...
  5. Secure the pipe. ...
  6. Install pressure limiting valve. ...
  7. Install different taps. ...
  8. Call the plumber.

How to remove air from a central heating system?

What do you do?
  1. Put all radiators on their highest setting. ...
  2. Switch the central heating off. ...
  3. Go to the radiator that is closest to the boiler. ...
  4. Place the screwdriver or radiator key on the bleed tap and turn anti-clockwise until water comes out instead of air. ...
  5. Close the bleed tap again.

How do I stop my furnace from knocking?

Ensuring that there is sufficient space for ductwork expansion and contraction is crucial in preventing knocking noises. Inspect the ductwork for any contact with other objects and determine if there's ample room for expansion and contraction could resolve the issue.

Why is there a weird knocking sound in my wall?

There is usually a simple explanation for why your walls are making a knocking sound. Most often, it's your home's plumbing system. It may be due to fluctuating water pressure issues, loose plumbing pipes, or a faulty valve.

Why does my wall heater tick?

Nov 14, 2022. If you're having problems with your heating system, the issue might be due to a damaged capacitor, especially if you hear clicking sounds from your heater. Clicking heater noises often mean your furnace's capacitor is failing and not properly regulating electricity to your blower fan.

Why does my central heating make a knocking sound?

Loud banging noises in the copper pipes could be caused by the boiler's thermostat set too high which is a symptom of overheating. Turn down the thermostat to see if that helps solve the issue. This is the most likely cause of banging pipes in a boiler installation.

Can a water hammer go away on its own?

Water hammer rarely goes away on its own; it's a serious plumbing problem you should address. Pipes can sustain damage from repeated impact, resulting in leaks or burst pipes. Fixtures like faucets and valves can also be affected by water hammer stress, leading to wear and tear or even failure over time.

How much does it cost to fix a water hammer?

A water hammer arrestor costs from $15 to $50. They're available online, at home centers, and in hardware stores. Most of the cost of a water hammer arrestor installation is in the labor. Calling in a pro will typically run $250 – $500.

Why is my HVAC making a knocking sound?

Common causes of a knocking noise from a heat pump include frozen outdoor coils, an unbalanced indoor fan, loose parts rattling, and compressor damage. The icing on coils forces the unit to work harder, causing vibration. Fan imbalances, loose parts, and internal compressor failures can also create knocking sounds.

How to stop a thermostat from clicking?

One way to dampen the sound is to install additional insulation around the thermostat. While it doesn't change the sound, it can make it harder to hear. Another option is to look at getting a smart thermostat with an integrated circuit.

Why is my blower motor making a knocking sound?

Unbalanced blower motor

An imbalanced or failing indoor blower motor or outdoor fan motor, or worn-out bearings also cause a loud banging or knocking sound. Improper installation, undersized ductwork, and failing compressor may also produce unusual system sounds.

Previous article
How much is labor to repair flooring?
Next article
What should you not use to clean windows?