Many householders wonder whether Combi boiler problems are common, before they make their replacement boiler decision.  Combi boilers are the choice of many householders and have the convenience of instant hot water’ when required – within limits.

The combination gas boiler is not new. They have a longer history in Europe but have now become the most common gas boiler in the United Kingdom. A quick check with traditional gas boilers reveals two major divergences which could be the source of combi boiler problems or their advantages. The central heating hot water circulation system is sealed. Having no open vents there is no requirement for a feed and enlargement cylinder in the attic. The hot water storage tank can also be spared as the heating boiler will have its own hot water storage vessel.

common combi boiler problems

Combination boiler systems offer many room saving and gas economy advantages for the small-scale household. It is possible to set up a complete central heating and hot water system by purchasing only a gas powered combination gas boiler with a balanced flue. Add in radiators and copper piping and you are then able to heat your home. Your first reaction maybe that we had forgotten some component parts. The hot water storage tank, the feed and enlargement cylinder commonly put in the loft, the central heating pump and other component pieces that central heating and hot water systems seem to need.

Surprisingly a combination heating boiler does not require any of these parts. With a combination you can dispense with the hot water storage tank, there is no requirement for an loft based feed and enlargement tank, the other pieces we have named are in reality built into the combi heating boiler. So you can see with a combination boiler you can save a sizeable amount of space within your home.

Domestic hot water is produced as required, turning on a hot water valve will flag the need to the heating boiler. Cold water is quickly heated up by the use of an efficient heat exchanger. Hot water circulating in the heating system is diverted to the heat exchanger. In this way new mains cold water is quickly heated before reaching the hot water tap. The design and instant on hot water from the mains can cause combi boiler problems if you are not careful..

The compact design and advanced electronics mean that combi boilers are more complex than the average or traditional boiler and this can lead to problems and difficulty for the issue to be diagnosed.

In hard water areas the combi boiler can scale up, like the element in your kettle. This problem requires the heat exchanger to be descaled regularly or replaced in the worst case analysis.

Instant hot water is not instant, there is a slight lag when you turn on the tap.  Also the hot water can stop flowing when someone else turns on several taps at the same time.  This combi boiler problem can be a real nuisance when you thought that you were taking a hot shower!

The shower and hot tap pressure is generated by the mains supply rather than the header pressure from a hot water tank in the loft.  This works well until the summer hosepipe issues when the water companies reduce water pressure.

The sealed system may not be fully sealed and leak pressure over time.  When this happens you will need to top up the water pressure through the combi filling loop.

So combi boilers have problems but remember they have many advantages for a smaller family in a smaller home.


If you have any problems with you combi boiler then please don’t hesitate to contact Heatcare Norwich Ltd at 07715 998479