Need help topping up your boiler?

November 28, 2017

Re-pressurising your boiler


Its getting colder and your using the heating more than ever. You want to make sure that the pressure in the boiler is at the right level to insure there is enough water to circulate, with low water in the system your boiler will probably overheat, underperform, and most likely lead to premature failure of components.


To save you calling out a engineer for a simple fix we put together this blog for you.



The water pressure indicator on the front of your boiler should read between 1 and 1.5 bars of atmospheric pressure. If it is below one, then your boiler pressure is too low. 


To top up your system and increase the pressure, you will need to locate your filling loop. This is usually a silver/grey coloured, flexible hose with a small valve at each end You’ll find it either underneath your boiler or nearby. Some boilers have a filling loop as part of the boiler. Below are a few of the most popular filling loops.




  Most common filling loop             Worcester Bosh filling loop





         Vaillant filling loop                 Baxi and Ideal filling loop



To top up your system firstly make sure the boiler is switched off and the system is cool.

  • The hose will have a valve at both ends – make sure both ends of the hose are securely attached to both valves.

  • The valves can be opened either by tap handles, or by using a flat headed screwdriver.

  • Open both valves to allow the cold mains water into the system.

  • You should hear water filling the system.

  • Keep an eye on the pressure gauge until it reaches 1 to 1.3bar, then close both valves, one after the other.

Once the pressure is at the required level, switch the boiler back on and (if required) reset the boiler.


If you continue to have pressure problems after re-pressurising your boiler, our expert engineers at LHS Plumbing can diagnose and repair the problem. 

Call us here on:  020 8111 1230


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