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Factsheets - Boiler breakdowns

Whilst all advice given is correct to the best of our knowledge, we cannot be held responsible for any problems should you choose to take our advice.

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Boiler Breakdowns

There are number of simple things that go wrong with boilers that you can fix without calling out a heating engineer.

You must make sure that you have the instruction/user manual for your boiler and the programmer/room thermostat. These are specifically designed to help you look after your boiler and central heating system.

Simple Fault Resolution

Pressure: Check the pressure in your boiler. Look for a pressure gauge on the boiler. Please Note: Some boilers are not pressurised, they have feed and expansion tanks in the loft.

If you have a pressure gauge, it should read between 1 to 1.2 bar. If it is below 0.25 bar your boiler needs to be re-pressurised. This means that there is no longer enough water in your system to maintain the correct pressure and needs topping up.

Please note that frequent drastic pressure drops suggest a leak in the system. A constant rise to 3 bar might be because the filling point has been left on and the system will then be over pressurised.

Look in your boiler manual for titles such as "re-pressurising, restoring pressure or water filling". Follow the instructions. Let in the water carefully a little at a time until it reaches the operating pressure. DO NOT OVERPRESSURISE as this will also cause the boiler to cut out (see above).

Temperature: If the radiators are not getting hot enough make sure that the thermostat on the boiler is turned up, especially in the winter. The room thermostat does not control the feel of the radiators.

If the temperature of the hot water is not hot enough make sure that the thermostat is turned up. On a combi boiler in the winter you might have to increase the temperature as the incoming mains water in the street is a lot colder.

Fuses: Check the fuses, are there any lights on the boiler? If not, look at the main fuse board if this ok, then change the fuse with a 3 amp one in the plug or the switch/fused spur feeding the boiler.

Programmers/Room Thermostats: Check these, the programmer controls the firing of the boiler. If this is set incorrectly your boiler will not work. Check the set times and temperature. If you are in doubt or the timing period is not turning the boiler on, place the programmer in the constant ON / 24hrs mode and make sure the boiler works.

Digistat (wireless controllers) are battery powered. Look for a warning light or icon that shows that the batteries have expired and change the batteries o r look for a continuous red light that means that the transmitter (the one with the temperature and flame in the window) and the receiver (the one with two buttons 1 and 2) are no longer talking to each other.

To reset pull the battery drawers out to the display in the window goes blank. On the receiver press and hold buttons 1 and 2 until the lights stop flashing. Hold the transmitter about one metre away from the receiver and push the battery drawers back in firmly. The receiver will flash and then you can use it as normal. If the power has been turned off for any reason you may need to reset.

Help us to help you

Please find out your make of boiler and model number (for example: Vaillant TurboMax Plus). This is either on the front of the boiler or just inside the flap which enables you to get at the boiler controls.

Look and see if the boiler is showing a fault code such F20 on the display. Please tell us this with the boiler information. This will help us diagnose your problem.

Please try to work through the symptoms of your breakdown logically so that you can help us diagnose the fault as quickly as possible. You might find, for instance, that you only have only hot water and no heating.

We hope that you find these tips useful. Of course, we cannot take any responsibility for the consequences of our advice.

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