The top five most common boiler problems

Common boiler problems make us think "expensive" immediately.

Complexity does not always bring more common boiler problems or faults but can mean that the average user is somewhat baffled or scared to touch what looks like a complicated and strange electrical wiring box.

The average gas boiler that now gets installed in your home looks far more complicated than ever before. Just like other kitchen appliances they are being controlled by smart electronic systems and devices.

This is fine and often the best course of action but there are some simple things that go wrong with a boiler that can rectify it and get you the hot water or heating that you need. Whatever you do it is always best to be safe and understand your limits especially when it comes to either gas or electricity.

Also if you have had a problem and solved it then it could quite easily happen again so get a plumber or heating engineer around as you never know what might be causing the problem with your central heating system to occur. Even a noisy boiler suffering from banging noises can have a simple solution.

5 Boiler problems to check before calling in help.

  1. One of the most common boiler problems has got to be around pressure. Nowadays and with 80% of all boilers combination ones that have a sealed heating circuit a lack of pressure means it will not function. Most boilers need to have around 1.5bar pressure in the system to fire up or work. If there is not enough pressure then the boiler senses that it will not be able to move enough water around the system so will go to lock out. Combination and system boilers all now have fault code diagnostics which are referenced in the manuals to explain the issues and common reasons for the problem you are experiencing. If you do top up the low water levels make sure you consult the boiler manual and do not leave the filler loop or cold feed in on otherwise that will cause the next issue.
  2. Over pressurisation is a result of too much water in the system and often the consequence of a too liberal fill after a pressure drop. This is common when a homeowner cannot get a boiler to work after a long period of non-use and the system is cold and they do not account for the expansion of water in the system when it is hot. If you have a pressure gauge refer to your boiler manual to identify the correct pressure range for your system. The system needs to be at the right water pressure since both low pressure and high pressure can cause issues with your boiler. Another symptom of over pressurisation is that your pressure relief valve may be leaking water. This water flow technically indicates that the pressure valve is doing its job correctly.
  3. Boiler in lock out mode and it will not function is very common and can be related to the above and also a lot more variables. Boilers shutdown because they have been manufactured not to cause catastrophic failure (the boiler is totally unrepairable or dangerous). Often it is a variable that can be rectified by just switching the boiler off for several minutes for it to clear the issue and then turn it back on and it may just work again. There is a sequence of firing and if any of these are not correct then it will not go to the next stage.
  4. Air in the system is not good for radiators, components and boilers. It can cause the circulating pump to seize and stop working or the boiler to lock out. It is easily remedied and does not require you to touch the gas or electric. Limescale, caused by hard water can also build up over time, and can cause issues with your boiler. This can be fixed by using chemicals to power flush the system.
  5. Heating and hot water not working or only working when i have them both on at the same time. Depending on what type of boiler you have will determine how your system operates. Combination boilers are a sealed unit and all the working items are internal. If you are getting heating and it is not switching over to hot water when you turn the tap on then more than likely the common cause of the problem is the diverter valve located inside the boiler casing. There are things you can do that are worth checking to remedy this but it is best to get a plumber out.

If you have a conventional boiler and the water pump and controls are outside of the boiler and you are getting the above symptoms then it could be any number of things that are wrong. If the boiler is firing up but the rads are not getting hot then check for a faulty pump and see if that is working. If it is and you are not getting hot water or heating then check the motorised valves. If your pump is leaking then it might mean the pump seal has failed and it'll need to be repaired.

Don't forget to check your thermostat since this is another item that cause problems. Thermostat issues can prevent the boiler working correctly. Also check your condensate pipe as in the winter a frozen condensate pipe can cause your boiler to switch off unexpectedly.

If your boiler has a water leak or issues with your gas supply then these are both considered serious issues and it is time to call in a professional. engineer or in the case where you smell gas, contact your gas supplier urgently and switch off your gas at the gas stopcock. Amateurs shouldn't mess around with gas appliances since these can be very dangerous.

I hope the above helps with some of the common problems found and please if you are unsure give us a call at Mr Central Heating. With anything that is warranty please check with the manufacture first to check it is not covered under warranty. Alternatively a gas safe registered engineers can also diagnose and help with boiler repairs. You may not necessarily need a brand new boiler, so don't panic if you do run into problems. Boiler issues do not always mean the worst case scenario.

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