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Noisy Boiler? Do this before you call an engineer

With temperatures suddenly falling lately, you may well have found yourself cranking up the heating in order to keep your home warm and comfortable after what has been quite a prolonged mild period - and you may also have noticed that your boiler has started to make unexpected and worrying noises. Check out these simple tips before you call an engineer.

Establish where the noise is coming from

The first thing to do is be certain where the noise is actually coming from. Although it may sound like something is wrong with your boiler, it is important to remember that your boiler is connected to your radiators by pipes that go all around the house - and they can carry sound just as well as they carry water! This means that although unfamiliar noises may appear to come from your boiler, they may actually be originating somewhere else.

The good news is that if you discover you have noisy pipes or radiators, your boiler is probably perfectly healthy and you will likely need to bleed your system

If you have checked and are still certain that it is your boiler itself making noises, we recommend you follow these steps:

Check for a boiler error code

Most boilers now have digital displays that will show an error code if a problem is detected. If you use an app to control or monitor your boiler, this may also give you information. If your boiler is displaying an error code, consult your handbook and follow any instructions given to rectify the problem. In many cases, a fault code will cause your boiler to stop operating, but you can often fix the problem and reset the boiler without needing an engineer to intervene.

If your boiler is making noises, but is still working and there is no fault code displayed, read on for further tips.

Finding your boiler manual

If you don’t have the original manual, you can find your boiler handbook using the links below:

If your boiler is making a ‘whooshing’ noise or vibrating

Is your boiler making a ‘whoosing’ noise or vibrating? Although this can be scary, there is probably no need to panic. In most cases, the problem is with the air supply and sounds much worse than it actually is. Here’s what to do:

1. Check for a blocked boiler air intake/flue

One of the most common causes of a noisy or vibrating boiler is a blocked air vent. Go outside and check if anything is blocking the external pipe on your building. The problem can be as simple as fallen leaves, feathers or even fluff. If this is the case, remove the blockage with your hands provided it is possible to do so (do not do anything that could risk causing damage to the vent). Once the vent is clear, you should be able to detect some air movement if you place your hand over the pipe.

Do not attempt to remove coverings or use tools - this should only be done by an authorised engineer.

2. Check the air filter

The second possible cause is the boiler air filter, which works the same way as the filter in your vacuum cleaner. Check your user manual to see if it is possible to clean this part yourself and if so follow the instructions carefully. A dry brush or a vacuum cleaner will usually be suitable.

Only perform this step if your handbook instructs you how to do this. You may need to have this done by an engineer.

If your boiler is making a gurgling sound

Remember, your boiler is constantly heating water and pumping it around your house, so some gurgling is inevitable. Although it may sound like the water is boiling, this is extremely unlikely and not something you should be worried about - there are safety systems in place to prevent this from happening.

If your boiler has started gurgling more than normal or more loudly than you would expect, the problem is most likely air in the system or low water pressure.

1. Bleed the system

A gurgling sound in your boiler is most likely to be caused by air in your central heating system. It may be accompanied by a cold patch on one or more radiators. The problem can usually be fixed by bleeding your heating system.

How to bleed your system

  • Set all of your radiators to maximum and run the heating at full temperature for 10-15 minutes
  • Turn the heating off at the boiler and wait until radiators are cool - this usually takes usually 30-60 minutes
  • Bleed the radiator nearest the boiler using a bleed key or screwdriver until water comes out
  • Repeat this for each radiator - be sure to fully close each bleed valve afterwards
  • Turn the heating back on and check the water pressure

2. Make sure the water pressure is correct

Gurgling sounds in your boiler can also be caused by low water pressure. The pressure gauge is usually found within the control panel or just beneath the boiler where the pipes are connected. The correct pressure is usually marked on the gauge by a pointer or a green region - usually 1 - 1.5 bar. If the pressure is below this, please see our article on how to repressurise your boiler for more information. If your pressure is dropping regularly, it is recommended to seek advice from an approved engineer.

3. Check the circulation pump

If you have tried the previous steps and your boiler is still making a gurgling noise, there may be a fault in your circulation pump. This is usually inside a modern boiler and will probably require a Gas Safe and OFTEC registered engineer. Apart from the sounds you are hearing, other signs that your circulation pump may be faulty can include:

  • Not all radiators are being heated
  • Your domestic hot water is not heating up

Never attempt to remove the boiler casing. This is only permitted by a Gas Safe registered engineer.

If your boiler is making a buzzing or whining noise

Your boiler should not make a persistent buzzing or whining noise usually. If your boiler makes this kind of sound, you should contact an engineer as soon as possible to avoid causing damage to your boiler. Possible causes include worn pump bearings, a defective burner or vibrating fans. Only a qualified engineer will be able to fix these problems.

Safety first

Always put the safety of yourself and others first. Never attempt to perform any maintenance on your boiler unless instructed to in the handbook for your make and model - this may be dangerous and against the law. If in doubt, contact a Gas Safe and OFTEC Registered engineer. For warranty repairs, always ensure your engineer is approved by the manufacturer.

If you are having problems with a gas or oil boiler, call D.R. Plumbing and Heating for reliable and trustworthy service throughout North Wales. Get in touch today on Wrexham 01978 291 923 or Mold 01352 620 125.

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