How does a System Boiler work?

A System Boiler, or sealed system, is a great option if you have more than one bathroom or your household has a high demand for hot water.


How does a system boiler work?


A system boiler contains all the major components of the heating system, including the pump and expansion vessel, which means installation is quick, neat and efficient. The boiler heats the water in a hot water storage cylinder, which in turn heats the water in the central heating system via a coiled heat exchanger and provides hot water to taps and showers.


Do I need a system or combi boiler?


If you have a high demand for hot water, for example, if you have more than one bathroom or shower room, a system boiler may be the perfect choice for you.


Will I need a separate expansion tank in the loft?


There is no need for a feed and expansion cistern in the loft if you have a pressurised unvented hot water storage cylinder. If you have an open vented hot water cylinder, you will need a cold water storage cistern in the loft.


Can system boilers supply several taps at once?


A system boiler is perfect for homes with multiple bathrooms; hot water is provided by a storage cylinder, so no matter how many taps you turn on, water will not run cold elsewhere in the house.

Our System Boilers

Our System Boiler heats up water in a sealed hot water cylinder, usually found in the airing cupboard, for hot water taps around the home.

Related FAQs

What should my boiler pressure be set at?

Normal operating water pressure for your boiler & central heating system is between 1.0 and 2.0 bar. Find out how to troubleshoot when the pressure drops.

Does my boiler filter need cleaning?

Ask your installer to clean your filter while carrying out your annual boiler service. Read more to find out why this is important...

Do I have to have a magnetic boiler filter installed?

Fitting a filter is considered best practice when installing a new boiler. The installer must carry out the following steps when a new boiler is fitted...

What is a back Boiler?

A Back Boiler is a small, compact Boiler fitted at the back of an open fireplace hearth. Find out everything you need to know about the Back Boiler.

What are the different types of boilers?

Read about the different types of Boilers, their pros & cons, so you can make an informed decision on what's best for you when you come to replace yours.

Show more