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Why is my Boiler Losing Pressure?

boiler keeps losing pressure

If your boiler keeps losing pressure on a daily basis with a lack of heat or even a warning message, you may need a boiler service. However, there are plenty of methods that you can do yourself to bring the pressure back to normal without the need of replacing your whole system.

You will more than likely notice a lack of hot water if you have lost pressure in your boiler but some will even make odd noises. In order to check the water pressure of your boiler, go to the pressure gauge on the boiler (you may need to remove a cover) and take a reading. It should read between 1 to 1.5 bar for optimal performance.

If it is reading less than 1 bar, you should repressurise?the system by adding more water back into the boiler. This is usually just a lever but we recommend that you read your boiler manufacturers guidelines on how to do this.

Boiler is Leaking

If you have increased the water in the boiler by repressurising the system but the water pressure decreases, you may have a leak somewhere in the system.

To confirm that this is the case, check over all the pipework and radiators. If you are still scratching your head trying to figure out where the leak is, it may be under your floorboards, which can be a big problem in some houses.

boiler losing water pressure

Faulty Pressure Release Valve

A faulty pressure release valve will result in a small but continuous amount of water leaving the system, which will reduce the pressure in your boiler. If this continues, it will result in an expensive boiler fault due to the constant lack of pressure. We recommend that you have a professional perform a full inspection if this is the case.

Faulty Pump Speed

Combination boilers need high pressure in order to function correctly but it is known for the pump speed to be set too high in some cases. This has the effect of causing cavitation and the production of oxygen inside of the system. Oxygen particles will then be released from the air vents and this ultimately drops the pressure down.


If you don’t want to make your boiler troubles worse or are unable to restore your water pressure, we provide our boiler repair in Cardiff and fix issues such as boilers losing pressure on a daily basis. If you continue to leave your boiler to lose pressure on a daily basis, something sooner or later will go wrong and it will be a more costly fix.

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180 Ffordd James McGhan, Cardiff, CF11 7JU
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