Why is my boiler losing pressure when the heating is off?

Having problems with boiler pressure dropping when the heating is off? If this sounds familiar, what is the best way to fix the problem? Let’s ask the experts.

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Having problems with your boiler losing pressure when the heating is off? If this sounds familiar, keep reading to uncover the best way to fix the problem.

Why is my boiler losing pressure when the heating is off?

The most likely cause of a boiler losing pressure when the heating is off is a failed expansion vessel.

A qualified Gas Safe registered engineer will check this by using a regular foot pump to repressurise the system.

If the system continues to lose pressure, then the expansion vessel will need replacing.

Are there any other causes for a boiler to lose pressure when the heating is off?

Yes. Another cause of a boiler losing pressure when the heating is off is a blocked pipe.

If a boiler retains pressure after being pumped, it means that the expansion vessel is fine.

If a pipe that leads from the expansion vessel is blocked, it can also cause pressure problems.

In this case, a Gas Safe engineer will be able to remove the pipe and clean out any blockages. Once replaced your boiler should retain its pressure whether the heating is on or off.

A regular boiler service can help to keep your boiler in good working order for longer and starts from around£100.

Call in the experts

It’s important to remember that you should always use a Gas Safe registered engineer when carrying out any servicing of your boiler. Without the proper qualifications, fiddling with gas appliances can be highly dangerous and potentially lethal.

Enter your postcode in the box below to find Checkatrade approved Gas Safe boiler engineers working in your area.