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Different types of boiler

There are three main types of central heating system and three different types of boilers to suit all types of property. Knowing which one is best depends on a number of factors but we are always happy to advise you.

Combi boiler

1. Combination boilers
These provide both heating and hot water without the need for a hot water cylinder. They’re good for showers and heating, they take up little space.

System boiler

2. System boilers
These provide heating from the boiler and hot water using a hot water cylinder. The cylinder and boiler can operate independently so that if the boiler fails the cylinder can be heated electrically.

If you want to run a shower on this system, it may require a shower pump but the cold water storage tank needs to be big enough to cope with the supply to the shower pump or else the pump may run dry.  Mixer taps don’t work when the hot water from the tank isn’t at the same pressure as the cold supply from outside.


System boilers and unvented cylinders are very good at supplying hot and cold water with excellent flow rates and can provide hot water to multiple showers and baths.  There has to be a good cold water supply to the house for this system to work. They have an expansion vessel instead of attic tanks. 


3. Heating only boilers
These are similar to system boilers but are generally found in older central heating systems. They rely hot and cold tank placed high up such as in the loft. They are less efficient but can be a good like for like solution.  It is a good idea check the ballcock assemblies and overflows in the attic tanks from time to time to avoid leaks through the ceiling.

We will happily discuss like for like changes of your boiler or upgrades to your heating system. Don’t hesitate to give us a call.