Troubleshooting a Noisy Boiler

Unusual noises coming from your boiler is almost always a sign of a problem and should never be ignored. A banging, gurgling, or humming noise could mean an issue that you need to get fixed as soon as possible before it can get worse.

Knowing the reasons behind the different sounds malfunctioning boilers make can help you determine what you should do next when your boiler is on the fritz. In some cases, you can use a DIY fix while other issues will require you to call a professional boiler repair company.

Boilers Making a Banging Noise

There are two types of banging noises your boiler may make – a single bang when it turns on or a continuous bang while it runs.

Delayed ignition is most often the cause of a bang when the boiler starts up. This occurs when there is:

  • A Bad Pilot Light
  • Not Enough Gas
  • Not Enough Air Around the Ignition
  • Dirt on the Burners

A bang when your boiler fires up is always a reason to hire a professional as this is a problem that gets significantly worse the longer it goes on, eventually causing the heat exchanger in your boiler to crack.

Recurring banging noises are the result of a problem called kettling. This is when the part that heats the water gets too hot and produces steam bubbles. When these bubbles burst, they cause the banging noise you hear.

There a few different issues that can cause kettling. These include low water pressure, a malfunctioning thermostat, or limescale deposits. This issue also requires a professional to determine the cause and fix the problem.

Boilers Making a Humming Noise

A continuous humming noise is usually due to a loose component that is rattling as your boiler runs. You should inspect your boiler when you hear the noise and look for a vibrating part or bracket. If you can find it, you can tighten it on your own. if the entire boiler is vibrating, that can indicate a larger problem, and you will need to contact a professional. 

The other cause of a vibrating noise is a problem with the circulating pump. This pump is on a pipe near the boiler. As your boiler is running, check for leaks or if the circulating pump is extremely hot, both of which need a professional. You can also try lowering the speed of the circulating pump and see if that fixes the issues.

Boilers Making a Gurgling Noise

Boilers will gurgle when there is air inside. This might be due to low water pressure, which you can check on your own by looking at the pressure gauge. The pressure should be between 15 and 20 psi. If it is lower than that you might have a leak, and you’ll need to have a professional repair the system.

Air can also become trapped in the boiler. You can fix this by bleeding your radiators either as a DIY boiler repair or by calling a professional. To bleed your radiators on your own, use the following process:

  • Turn On Your Heat – Turn the heat on and let the radiators warm up. Once they are warm, take a moment to locate any cool spots by placing your hand just above the radiator. A cool spot indicates an air bubble, and confirms the radiator needs to be bled.
  • Turn Off the Heat – Shut the heat off and wait for the radiators to cool down so that you are not at risk for a burn.
  • Open the Radiator Bleed Valve – Each radiator has a bleed valve that you can open with a screwdriver or bleed key. Open the valve just slightly to let out a few drops of water, then close the valve again.

You will need to repeat this process on every radiator on the property to fully remove any air bubbles trapped in the heating system.

If you hear a different noise coming from your boiler or are still unsure what the cause might be, it is always best to reach out to a professional technician. Boiler problems can become expensive very quickly, but a boiler repair company like Empire Plumbing Inc in NYC can help troubleshoot the issue and get your boiler functioning as it should once more. Call us today to schedule an appointment with one of our boiler repair specialists.

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