A noisy boiler can be very disconcerting, especially if you don’t know the cause and inconvenient if it wakes you up when you are sleeping. It is safe to say it is a sign that the boiler needs some attention. The noises can range from humming and whirring to clicking, knocking and even full-blown banging.
The main causes of noisy boiler problems and how to solve them:
The main cause of a boiler knocking noise / gurgling would be due to the build up of air in the system. You will need to bleed your radiators (find the bleed valve and release the air from your system) this should resolve your noisy boiler problem. As well as causing a noisy boiler, trapped air can lead to corrosion of the radiators, so will need to be dealt with as soon as possible.
Trapped air can cause loud banging noises and in worse cases lead to a build up of sludge in the system, this will require a power flush, as if left unresolved, a noisy boiler will be the least of your problems. Some of the problems you could end up with are higher fuel bills, boiler problems, or cold spots in radiators and reduce the life of your boiler.
The pump is another cause of a noisy boiler, usually a humming noise. It will cause a loud vibration if set too fast, you may want to turn it to a lower setting.
The pipe may be too small for the volume of water trying to get through and may need to be replaced to eliminate your noisy boiler problem.
Another cause of a noisy boiler is a faulty expansion tank or fast closing zone valve. These parts will need to be repaired or replaced if they are not functioning properly.
You should also check to ensure the thermostatic radiator valve (TRV) is not faulty and that it was installed facing the correct direction. If the TRV is facing the wrong way the water will flow in the wrong direction causing banging when the valve opens/ closes.