How to check & re-pressurise your combi boiler.

If you’ve noticed that you don’t have any heating or hot water, the problem could be your boiler pressure.

If the pressure of your boiler has dropped, you may need to re-pressurise your boiler.

You can check the pressure of your boiler and re-pressurise it yourself without having to call-out a Gas Engineer.

This post explains everything you need to know when it comes to re-pressurising a combination boiler.

How do I check my boiler pressure?

You can check the pressure of your boiler by looking at the small round gauge on the front of your boiler. You will notice a SAFE Green Zone and the Maximum pressure with a Red Zone. Some boilers have digital gauges and these will show if the pressure is too high or too low by flashing the reading on the boiler display screen.

The pressure of your combi boiler should be between 1 and 1.5 bar when the system is OFF & the water is COLD. It is perfectly normal to see your gauge rise when your heating system is on & the water is hot.

If your pressure is less than 1 bar, it’s possible that you have lost water from your system via a leak. If you find a leak or suspect that you have one, you should call us on 0116 287 8000 & we will be able to investigate and fix the problem. If you think that the pressure has dropped gradually over time, you can top up the boiler pressure yourself.

How do I re-pressurise my boiler?

Every type and model of boiler is slightly different so please double check your boiler manual for instructions on how to re-pressurise your combi.

  • Switch off your boiler and allow it to cool completely
  • Check your heating system for leaks

A good place to check is around your radiators & pipework, a leak on a radiator valve could be a reason for losing system pressure, also check your carpets & ceilings for damp patches & airing cupboards for any other leaks.

If everything seems okay, proceed to the next step, if you find a leak you should call us on 0116 287 8000

External filling loop type

A Boiler Filling Loop provides a temporary connection to the mains so that you’re able to re-pressurise and fill your heating system with water.

Filling loops can come in different designs and can be detached from the boiler when not in use.

With the black levers in this position the valves are OFF/CLOSED.

  • Find the filling loop and check that both ends are securely attached.
  • Open both valves by turning them through 90 degrees so that they are inline with the pipes, this allows cold water to enter the system
  • Keep an eye on the pressure gauge & close both valves when the pressure gauge reaches 1.5 bar
  • Remove the filling loop & re-fit any caps (if appliable)
  • Turn the boiler back on and recheck the pressure gauge
  • Depending on your boiler make/model you may need to reset your boiler – if you are unsure check your boiler manual
  • Open a hot tap & check that your boiler fires & your water heats up

Internal filling loop type

The Worcester Keyless Filling Link allows you to quickly and effortlessly re-pressurise your heating system without the need for a separate filling loop or key. The keyless filling link is quick to locate & makes re-pressurising your heating system easy

  • Locate the Small BLUE Lever beneath your Worcester combi boiler
  • Pull the lever down and hold
  • Keep an eye on the pressure gauge & release the lever when the pressure gauge reaches 1.5 bar
  • Turn the boiler back on and recheck the pressure gauge
  • Depending on your boiler make/model you may need to reset your boiler – if you are unsure check your boiler manual
  • Open a hot tap & check that your boiler fires & your water heats up

By re-pressurising your boiler, you’re allowing more water to enter the system from the mains supply. If you accidentally over-pressurise the system, don’t panic. You may need to bleed your radiators to bring the pressure back down to 1.5 bar.

You should keep an eye on the pressure over the following days and weeks to make sure the pressure doesn’t drop again. If it does, there’s a chance you may have a leak.

Below is a really helpful video from Worcester Bosch on how to top up your boiler pressure using filling loops, links & keys.

https://www.worcester-bosch.co.uk/heating-advice/boiler-pressure

 

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