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Boiler making noises? Here’s what to do before you call an engineer

As long as we have hot water when we need it and our house is nice and warm, we don’t really think much about our boiler - even though it is the heart of the home. If your boiler has started to make unfamiliar noises, however, you may well be worried. Before you panic and call the engineer, read on to learn more about when boilers make noises and what you should do about it.

Check if the noise is coming from the boiler

This may sound like an obvious question, but is the noise coming from the boiler itself? Because your boiler is connected your radiators by pipework that goes all around the house, the sound may appear to come from your boiler but actually originate somewhere else. Sound travels very easily through pipework.

Before reading on, listen carefully to check if the noise is coming from within the boiler housing or is elsewhere in the central heating system. If you have noisy pipes or radiators, you will probably need to bleed your system.

If you are certain that it is your boiler making noises, we recommend you follow these steps:

Check for a boiler error code

Your boiler is designed to display error codes if a problem is detected. A serious fault will cause your boiler to shut down, while some faults may simply require you to take action when possible. In some cases, your boiler may not register a fault code - in this case, the following sections may help.

Finding your boiler manual

If you don’t have the original manual, you can find an electronic version using the links below:

If your boiler is ‘whooshing’ or vibrating

A whoosing or vibrating boiler can be scary, but there is no need to panic. The problem is usually with the air supply and sounds much worse than it actually is. The following actions are recommended:

1. Check your boiler air intake/flue

The most common cause for this behaviour 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 leaves, feathers or even fluff. Remove the blockage with your hands if this is possible to do. Once this is done, 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 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 gurgling

Remember, your boiler is constantly heating water and pumping it around your house, so some gurgling is inevitable. If your boiler has started gurgling more than normal or more loudly than you would expect, the following steps may help. Although it may sound as if the water is boiling, this is extremely unlikely to be the case - your boiler has plenty of safety features to prevent this from happening.

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. Bleeding the system to get rid of any trapped air will usually fix the problem

How to bleed your system

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

2. Make sure the water pressure is correct

Gurgling sounds in your boiler can be caused by low water pressure. The pressure gauge is usually found within the control panel. In some cases, it may be 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 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 buzzing or whining

A healthy boiler should not make a persistent buzzing or whining noise and if this is the case, it is recommended to contact an engineer at the earliest opportunity 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 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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