Boiler pressure refers to the balance of water and air in your central heating system. Boilers need to be at a certain pressure for the heating system to work properly. It’s a good idea to check your boiler pressure once a month to ensure it’s working correctly, with additional checks (or even a boiler service) taken if you’ve recently turned the heating on after a long period of inactivity – for example, turning the heating on in winter if it’s been off all summer.
Monitoring the boiler pressure can alert you to any potential issues with either the boiler itself or the wider central heating system. All boilers have a pressure gauge that shows the boiler pressure, usually on the side or front of the boiler. Gauges can vary from make to make but usually look like a circular face with a dial that indicates the pressure number out of 4.
Some boilers may indicate normal and problematic pressure by using green and red bars on the gauge. If the needle is pointing to a green bar, the boiler is within a healthy range.

What is the right pressure for a boiler?

When the heating is switched off, your boiler pressure should sit around 1 – 1.5 on the gauge, moving up to 1.5 – 2 when the heating is switched on, although these numbers can fluctuate slightly.
If you find your pressure is too low or too high, you can easily increase or reduce the pressure by yourself. You can check out our guides on how to increase boiler pressure and decrease boiler pressure if you want to learn how.
If you adjust the pressure and it quickly reverts back to too low or high, you’ll need to contact a Gas Safe registered engineer to check for any faults that might be causing this.
We offer a call out service to help with any boiler or heating system issues – get in touch to arrange.