Combi Boiler Keeps Cutting Out? Find Out Why

It’s always annoying when a combi boiler cuts out. You are left with no hot water or heating, wracking your brains to try and figure out why exactly this keeps happening to you. Combi boilers are great for smaller homes as they allow all of your water heating and central heating to take place in one single, compact unit. However, it does mean that problems leave you with absolutely no way of keeping warm. Luckily, there are a number of reasons that a combi boiler may cut out and many of them are easily solved.

Low water pressure

Any combi boiler will need enough water pressure to run properly. The pressure gauge on the boiler should be between 1 and 2 bars – anything lower than this is insufficient for a combi boiler to work. If your boiler has low water pressure, it may mean that there is a leak somewhere in your system.

To find where these leaks are located, you should keep an eye out for damp patches around your home. Leaks can be serious so if you do find one, you should turn off your water supply and contact a heating engineer. Some people may be able to restore the water pressure back to normal themselves, however, it is always best to seek the help of an expert if you are unsure.

Airlock

Sometimes, air can become stuck in your hot water or central heating system. This trapped air can become a block that will prevent hot water from circulating as it should. Airlocks can prevent hot water from running out of your taps or could stop your radiators from heating up. Either way, it is a frustrating circumstance for any homeowner. Airlocks can be fixed by a professional or you may be able to fix them yourself. The best way to do this is by attaching the hot water outlet to the cold water outlet with a hosepipe and letting the cold water run through to the hot water tap until the airlock is released.

Damaged pump

The heating pump is one of the most important parts of any combi boiler system. The pump helps to circulate hot water around the heating system. Every now and then, the heating pump may become blocked due to the build-up of debris. This problem mainly occurs in older building systems and it is always a good idea to ask a professional for help. A heating engineer will fix a blocked pump by running a hot flush which will clear out any blockage.

Blockage in the main system

Just like the water pump, your heating system may be susceptible to blockage. Limescale and rust are amongst the many things that can build up in the system and cause a blockage. Not only will this kind of blockage cut off your combi boiler but, it will also affect the efficiency of your system and may cause it to start playing-up earlier than expected. The best way to stop a build-up in the main heating system is to have a magnetic filter installed by a professional. Magnetic filters work to pick up any rust or debris that may be floating around your system so that it doesn’t have the chance to build up and cause a blockage. This method only prevents blockage. To deal with a blockage that has already occurred, you will need to hire a professional to perform a power flush which will completely clear out your combi boiler system.

Lack of fuel

Combi boilers need a sufficient amount of fuel to run properly, whether that be from gas, electricity or even oil. If your boiler isn’t receiving enough fuel, it may be unable to run and will cut out. The most common reason for this to happen is that prepaid metres have a lack of funds. If your boiler cuts out, make sure to check that your metre is topped up. Another cause of this problem is the pipes that connect your combi boiler to the gas meter. If your combi boiling system is older, it may have 15mm pipes which won’t supply enough gas to your boiler to run it properly. It is recommended that the pipes are 22mm – these pipes will let a sufficient amount of gas through to your boiler. If you need the pipes on your boiler changing, ask a registered engineer to replace them for you.

The condensate pipe is frozen

Condensate pipes are essential for keeping your combi boiler system running properly. These pipes drain acidic water outside and dispose of this waste into your drain. This is essential as acidic water can be dangerous. As they are outside, condensate pipes are known for freezing which can cause a block in the system. When the pipe is blocked, waste cannot be disposed of so the combi boiler will cut out. You may be able to fix a frozen condensate pipe yourself, however, it may be wise to ask a heating engineer. The pipes are fixed by carefully thawing out the blockage.