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Why is my boiler making strange noises


The cold season is upon us; make sure your heating system is in order always.

Strange noises can make your house seem like a haunted house. These noises can be very startling at times and much worse when you don’t know where it is coming from. Most of the time, these strange noises are coming from your boiler or plumbing. 

What is a boiler? A boiler is a closed vessel where water is heated under pressure, the generation part of a steam system makes use of a boiler to add energy to the feedwater supply to generate steam. The boiler circulating pump is what then carries your heated water from the boiler where it is heated into your home and also carries water back to the boiler. In most homes, the boiler just hangs on the wall and performs its job.

Our boiler is something we take for granted most times; most people are under the impression that as far as there is a constant hot water supply and heat supply, everything is just fine. There is no need for maintenance of any sort, apart from the annual checks at the beginning of the cold season. It is important to note that doing this is not right because anything can go wrong; a strange, unfamiliar noise can be the first sign. You should never ignore a noisy boiler; the best bet will be to contact reliable boiler repair services to investigate and fix the problem. In the meantime, we will be giving you the possible sources of boiler noise. 

Read also Rheem Water Heater Problems >>>

Most common causes of a noisy boiler 
  • Limescale
  • Malfunctioning thermostat
  • Airflow blockage
  • Insufficient water supply
  • Overheating
  • Reduced water pressure

Identify where the noise is from

The first thing to do is to pinpoint where the noise is coming from exactly. You need to identify if noise is from your boiler or from a home radiator or circulating pipe. If you hear just a creaking sound, it might just be the pipe adjusting to a change in temperature, and this is normal. As soon as you can pinpoint where exactly the noise is coming from then, you are one step closer to identifying the problem.

Identify the type of noise from the boiler. 

Different sounds can come from your boiler. Here are some of the sounds and the possible reasons behind them. 

Loud humming noise 

A humming sound can come from your water heater, it might be as a result of a loose bracket that needs to be tightened, and you can tighten this yourself. Water heaters can also make a rumbling sound because of limescale heating and expansion in the cylinder, rust, and sediments. This rumbling sound can also be due to increased pressure causing the valves in your home to hum; always check if you need to readjust the pressure. 

Another reason why you might hear this sound may be that your pump is set too high; this causes the heated water to circulate too fast in the pipes. You thus should adjust the pump. Lastly, this humming noise may be caused by the fan inside your boiler, most especially the bearings in the fan. At this point, if you still can’t figure out why this is happening? It is best to contact HVAC repair experts that can get this checked for you.

Gurgling Noise

This can happen due to trapped air in the boiler. Normally there is not supposed to be air in a boiler. When air is present, corrosion occurs. Nevertheless, air can get into the boiler through leaks in the piping system. You can solve the problem of air trapped in the boiler by bleeding the radiator, which involves switching the boiler off, allow to cool off, turn your internal filling key to let cold water in to repressurize, and turn on the boiler. If the boiler keeps losing pressure, then there is a leak. Make sure to fix those leaks immediately.

Another issue that can cause this sound is a frozen pipe somewhere that is making water back up in the boiler. In this case, you will need HVAC repair experts to thaw the pipe for you.

Kettling noise

The kettling of trapped air inside the central heating system can be the reason for this noise. The first thing to do will be to bleed the radiator; you can do this yourself if you know how. Remember to always check the boiler’s pressure afterward. If, after bleeding, the noise continues, then kettling will be the next suspect as trapped air has been ruled out. 

Kettling sounds like the whistling of water when it has come to a boil. This is caused by an accumulation of debris from corrosion or limescale, which can be inside the boiler itself. Lime scaling is a natural process and tends to happen in regions where there is hard water. Limescale can cause water flow restriction, which leads to trapped water. This trapped water tends to heat up too much, starts boiling, and turns to steam, eventually causing the whistling. This might not be an easy fix, and you may need to get central heating system repair services. 

Banging Noise

These loud banging noises may be due to kettling. As you know from the previous explanation, kettling is caused by the build-up of limescale, sludge, corrosion debris in the heat exchanger. This can block the water flow in the heat exchanger, which in turn leads to the heating up of water and the production of steam. The sound generated from this is most times accompanied by Banging noises. It is necessary to get central heating system services because the build-up is not easy to fix. 

Tapping noise

The tapping noise most probably is coming from your pipes and maybe as a result of overheating. Check your thermostat by turning off the boiler, cool the system, turn it back on again and turn up the thermostat. It should click, but if it doesn’t, it is necessary to get boiler repair services. This tapping noise can also be a result of kettling. In this case, you also need boiler repair services.

Drone noise

It can be very alarming when your boiler starts to sound like an airplane or a drone. There are various reasons why this may be happening; it might be a simple pump failure or air in the impeller; as soon as you notice that the pump in your boiler is affected. You should call an engineer to fix the issue; you might need to change the boiler if there is internal damage. 

Always run a regular maintenance check on your central heating system and not just annual maintenance; you can always get affordable boiler repair services around you to do this for you. 


5 Star Plumbing Offers High Quality, Professional Boiler Maintenance And Repair Service. 

Have you noticed any strange noise coming from your boiler? Have you tried to get rid of it to no avail? Do not stress anymore – call 5 Star Plumbing for boiler maintenance and repair services. We are a recognized and licensed plumbing service company. We provide plumbing installation, repair and maintenance services in all types of properties – residential and commercial. Our workers are trained and skilled to fix any issues with your plumbing system efficiently. You can hire them any day, and they will come to your home promptly, on time and with all the tools necessary to perform their job.

To schedule an appointment with one of our experts, just give us a call at (888) 909-0120 or leave us a message online. Our customer service representatives will help you book a technician and also answer any questions you may have.


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