Why does my boiler pressure keep going high and how to fix?

One common issue faced by homeowners is when the pressure in their boilers becomes too high.

With so many being unsure as to what causes this and when this pressure is too high, we have decided to answer some often-asked questions.

When is my boiler pressure too high?

Boiler pressure is too high when the gauge dial reaches the 'red zone' (Getty) (Image: Getty)

Your boiler pressure is too high when the gauge dial has gone into the 'red zone' (bar three or above) and/or when the system has shut down.

Alternatively, if your pressure is too low, it will fall into bar one, according to Green Star.

Why does my boiler pressure keep going high?

According to EDF Energy, there are a number of reasons why your boiler pressure may be too high.

You may have accidentally put in too much water when trying to correct low pressure.

You may have also left the filling valves open and/or not screwed or shut them tight enough, allowing water to continue flowing in.

How do I lower my boiler pressure?

One way to lower water pressure is to turn the boiler off and check that the filling loop valves are closed properly.

Once this has been done, you can then allow the system to cool and begin bleeding each radiator.

If the pressure is still too high, you should repeat the process until the pressure is back in the neutral zone.

Bleeding your radiators is one way to deal with high boiler pressure (Getty) (Image: Getty)

To bleed a radiator you will need a cloth or towel, a container to catch water and your radiator key or a screwdriver.

Once the valves (usually located on a corner) are loosened, you should hear a hissing sound as the pressure is released. 

When you begin to see water gush out tighten the valve.

Why is my boiler pressure too low?

Low boiler pressure can be caused when there is a leak in the system, causing pressure to be lost.

Damp spots, flaking wallpaper and/or paint are common signs that there is a leak.