How can I check the pressure of my boiler?

Your boiler must have the right amount of pressure for the hot water to circulate around your house efficiently and keep you warm and cosy.

How can I check boiler pressure?

  1. To check the pressure you’ll need to locate the pressure gauge on your boiler.
  2. If it’s at the correct pressure the needle will be located between the 1 and 2 bar.

Most boilers detect when pressure isn’t correct and will cut out when the pressure is too low. If your boiler pressure is low (with the needle below 1) your boiler will turn off and you’ll be left with no hot water. And if your boiler pressure is too high (needle above 2) it could potentially break your system.

Boiler pressure generally should be between 1 and 2, but it’s best to read your manual to double check. The area between 1 and 2 on the gauge is usually seen in green. When pressure is over 2 it’s increasing the stress placed on your system including pipework radiators and components, which could lead to potential issues.

What if my boiler pressure is too low?

A filling loop

If your dial falls below 1 and into the red zone, you’ll need to top up your heating system. Re-pressurising, or ‘topping up’ your boiler means allowing water to enter the system from the water mains supply via the filling loop. We always recommend consulting your boiler manual for instructions on how to top up your system, but here’s how it’s generally done:

  1. Turn off your boiler and wait for the system to cool
  2. Attach the filling loop from the non-return valve to the isolation valve
  3. Double-check that both ends of the filling loop are securely attached
  4. Open both valves slowly to allow cold mains water into the system. You’ll be able to hear it filling
  5. Watch the pressure gauge until it reaches 1.5 then close both valves
  6. Switch your boiler back on
  7. Undo both ends of the filling loop and remove it. Watch out for any loose water caught in the filling loop!

What if my boiler pressure is too high?

If the boiler pressure is too high then you may need to bleed your radiators. Check out our blog on how to bleed your radiator.

If you’re not confident about re-pressurising your system yourself, or you think you may have a bigger problem, then don’t hesitate to give Glow a call. Our Gas Safe engineers will be able to detect the problem, give you a fixed price and get your boiler sorted.

And if you’re a GlowPlus customer, we’ve got you covered. Just give us a call to get booked in.