How to fix low Boiler/System pressure

How to increase boiler pressure

Pressure loss is the most common boiler pressure problem you’re likely to come across. It might happen a couple of times a year, but it’s very easy to fix.

If you have a system or conventional boiler with a pressure gauge near your hot water cylinder, you’ll have a valve in the pipework – usually near the red vessel and the pressure gauge. Just open this valve a little and you should see the pressure gauge rise. Keep filling until it’s between 1 and 1.5 bar, then close it.

If you have a combi boiler, just follow these step-by-step instructions:

• Switch off your boiler and allow it to cool

• Double check that both ends of the filling loop are securely attached

• Open both valves (or just one, if that’s what your filling loop has) to allow cold mains water into the system. Listen out, you should hear it

• Wait for the pressure gauge to reach 1 to 1.5 bar

• Close both valves, one after the other (or just the single valve, if that’s what you have)

• Switch the boiler back on. If needed, press the reset button

• Undo both ends of the filling loop and remove. Be careful to catch any water spillage and keep the filling loop in a safe place

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This is a common filling loop you may find:

Other types of filling loops/keys or levers you may have: