10 Common Boiler Faults

Matt Robinson | Updated on March 24, 2021
10 Common Boiler Faults

In this article I will share with you the 10 most common boiler problems that our gas safe engineers fix.

1. No supply of hot water or heat

One fine morning you switch on the boiler to discover that you are not getting the supply of heat that you used to get every morning. Some of the probable reasons could be broken airlocks, diaphragms, thermostat issues, motorised valves not working or the level of water is very low. It is very important to check whether the boiler has stopped functioning due to the thermostat or boiler pressure. In case the diaphragm is broken, the airlock or the valve is also broken; you need to call the engineers for a replacement. Call someone or a team that can diagnose the real problem and can offer you with flawless replacement.

2. Dripping and leaking

This could be caused due to a number of issues but the most important thing is from where is the water dripping and the cause of it. It is dangerous and not recommended to mend a leaking boiler yourself, you must always hire a Gas Safe and registered engineer. Leaking and dripping are mostly caused due to the breakage of any internal components like a pressure valve or pump seal. If the pressure valve is leaking, it is likely that your boiler pressure is very high. If the water drips from the pump seal, it needs to be replaced with a new one. Sometimes the boiler also leaks around the tank or pipes; it might be due to corrosion or because of faulty installation and fitting. Call an engineer for diagnosis, it can be repaired but you can opt for a replacement if needed.

3. Kettling

Are you getting a sound from the boiler which is akin to a boiling kettle? Sometimes there is a build-up of sludge or limescale in the heat exchanger of the boiler and this is when the sound comes out it’s called kettling. The deposits that build up usually restrict the water flow inside the heat exchanger. This leads to overheating of the water, therefore it boils and steams give rise to this kettle boiling sound. In areas where there is hard water, this symptom is very common. Due to this, the boiler works with more effort, and this increases the running cost and decreases the life of the device. Call a Gas Safe specialist engineer who knows the right technique to flush out the system for removing the deposits and build-ups and makes sure the system is functioning rightly.

4. The pilot light not coming on

The tiny blue flame remains on to alight a bright burner flame, this small one is the pilot light. But this light can go out anytime if the thermocouple is broken, this cuts off the gas supply and the pilot light goes out. Sometimes there is a deposit built up in the pilot light which leads the flame to go off. You can try re-igniting it but before that, you need to check whether there are any inconveniences with the gas supply. If it might happen that your gas stop clock is switched on yet the boiler is deprived of gas supply or the gas appliances are not working, get in touch with your gas supplier. If things are not working then call your registered engineer from a reliable boiler servicing company. Do not tamper or do any work alone with your boiler.

5. Radiators not heating up properly

It’s very common that radiators do not tend to heat up properly but this could be due to the presence of air inside the system or sludge build-up. The radiator requires bleeding in the case on the bottom of the radiator is getting hot. You can do it yourself, it’s easy but id you find it difficult there is always a professional to perform. In case some of the radiators are not getting hot, then you need to balance your radiators, adjust the valves on every radiator and this would ensure you are getting sufficient hot water. The professional has chemicals that help to flush the system. Try it yourself only if you are confident.

6. Low pressure of the boiler

It?s very simple to check the pressure of your boiler. If the needle remains below 1, then it could be a problem of low pressure and this slows down your heating system. Now take a look at the reasons why this could happen:

  • Water leakage in the system
  • Radiators have bled recently
  • You need to replace the pressure releasing valves

Check for any visible leaks in the system, if you find any then call an engineer. If you do not find any leaks, then re-pressurise the system. There are lots of instructions to be followed during the process, therefore call a certified professional.

7. Issues with the thermostat

It might happen that your thermostat is losing accuracy upon turning it on and off. In situations like this, it could be that you need to buy a new thermostat. But it’s always better to perform a few checks like whether it is on position and whether the setting of time is correct or not. In case it’s knocked, there could be certain issues. There could be other thermostat issues as well. When it comes to thermostat problems, it is better to invest in a new one because these devices lose accuracy over time and mending is not a great idea.

8. Frozen condensate pipes

9. Boiler switching off automatically

It could be because of low water pressure, a dearth of water flow because the valve is closed, pump or air not circulating, thermostat problems and more. In this case, you have to call your engineer for a checkup.

10. Unusual whistling, banging or gurgling noise

It’s a very common issue that air gets inside the system. Above it’s already mentioned that kettling is another issue of low water pressure. If there is a pump failure, your system could emit banging noise. An expert is able to determine the problem based on the kind of noise the boiler is making. Boiler whistling and boiler gurgling are two very common types of noise issue in boilers. Boilers are usually not silent but it’s not a positive sign if the device is making too much noise. Any unusual noise must be investigated sooner, this way you can save money that you would be shelling out on expensive repairs.

Should I replace my boiler?

Have you installed your boiler ten years ago or even more? If your boiler is running for 10 years, you must consider a boiler replacement. Older boilers are generally prone to faults and they lose efficiency over time. If you don’t take any action, your boiler will eventually suffer a breakdown. A new boiler comes with a warranty; this will lower your heating bills and make your dwelling safer. There are a variety of central heating systems and boilers in the market and each piece is a creation of technology. This is why if technology fails anytime, the repair tends to be very costly. Sometimes the faults are such that it’s worth repairing but there are times when you have to plan a replacement.

Regular servicing is a must

Yes, boiler servicing involves a bit of expense and when your boiler is working fine, you are not bothered about servicing. But skipping periodic boiler servicing is not a good sign. A system continuously giving out hot water can get tired and break down. Regular boiler servicing makes it easy for the technician to detect any problems before the thing gets worse. The majority of boiler faults happen due to inefficient maintenance. A service does not take too long to carry out, it’s just a matter of half-an-hour and your boiler is fit again. A lot of people ignore the servicing due to a long warranty but the truth is the warranty depends on annual boiler servicing. To maintain and increase the efficiency of the boiler, you need to keep an eye on the water pressure of the boiler. In case the boiler is on the lot for a long period of time, the water pressure begins to drop gradually with prolonged use. This is when you require adding water to the system and this will make sure that the boiler will operate in an efficient manner.

Most of the modern boiler these days is self bleeding; this is, in fact, great because you do not need to bleed the air out frequently from the radiators. Check your radiator on a periodic basis; say one in every two months with the help of the radiator valve key. This makes sure that the boiler is free from the air and operating efficiently. There is something called boiler draining, you can think of doing that once a year which involves flushing the boiler with an anti-sludge liquid. This keeps the system free from sludge. When there is sludge inside the system, the water pump needs to put in a lot of excess effort to function. If you are confident, you can carry the maintenance yourself but the experts are always there for you. The bottom line is, to avoid boiler faults, an annual boiler is highly recommended.

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