How to re-pressurise a sealed central heating system

25 November 2019

Some central heating systems have a small header tank, usually located in the loft, and will not need re-pressurising. Other systems, known as ‘sealed’ systems don’t have a header tank but instead have a pressure vessel, either inside or close to the boiler, along with a pressure gauge. If you have this type of system, sometimes you might find that the pressure drops.

The manual for your boiler should tell you what the correct pressure should be. It should also give instructions on how to re-pressurise the central heating system.

Overflows and warning pipes…

If you notice water dripping or flowing from an overflow or warning pipe, you should identify the cause without delay. It may indicate that a valve has developed a fault and needs attention.

Every new-build home in the UK that is sold with an NHBC Buildmark warranty and insurance policy comes with a secure, online Home User Guide (HUG). HUG is a free, personalised portal where you can store all the information you need about your home. It also contains useful advice about moving into a new home, designed to help you settle in as smoothly as possible.

This how-to guide is just part of the guidance available on HUG. If you’re in the process of buying a new-build home, or have recently bought one, with Buildmark cover make sure you check out HUG. It’s also the place where you can most conveniently accept your Buildmark cover.

Remember, most repair and maintenance ought to be carried out by a professional.

Take a look at our other how-to guides:

How to attach pictures, shelves and curtain poles

How to attach a floor fixing

Decorate your new-build home

How to connect a kitchen appliance

How to bleed a radiator