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10 Most Common Boiler Problems

Nov-2019 / < 1 min read

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  • As Murphy’s law would have it, the majority of issues with water boilers occur during winter. This is actually due to the water boiler having been inactive for so long: when it’s forced back to life, considerable pressure is put on it to perform, which can result in issues and the need to repair the boiler.

    While there are some boiler issues that can be quickly addressed, others require the help of a qualified professional. Remember, it’s always good to seek help from a professional gas engineer if you are having any doubts about the nature of the issue and make sure that from the start you’re boiler is installed correctly.

    Dripping and Leaking

    If your boiler is dripping or leaking, you could be looking at one of many issues with your boiler. This is mainly going to depend on where the leak is. The first and most common issue is going to be a broken part inside. This could be a broken pump seal or a broken pressure valve.

    If your pressure valve is leaking, then the pressure may be sitting too high. If the water is coming from the seal, then it may need replacing. Your boiler could be leaking around the tank area as well, which could be the result of corrosion.

    Low Pressure

    It’s easy to check the pressure of your boiler – all you need to do is find the gauge that will be on the side and check it for the pressure. If it’s reading low pressure, then your boiler may be faulty. This could be anything from bled radiators to leaking water and even a fault in the pressure relief valve.

    The first thing to do is to check for a leak anywhere, and if you find one, it’s crucial that you call a professional. You could try re-pressurizing your system if you don’t see a leak, but again it’s recommended that you get a professional to do this.

    Gurgling and Whistling Noises

    If you listen out for your boiler and it seems to be making strange noises, this could be trapped air it system. Another reason for this is low water pressure. You could even be dealing with a faulty pump, which is quite a common problem, particular in older models.

    You may be able to work out the cause of the noise based on what the noise is. Remember, if it sounds like a kettle boiling, it’s going to be ‘kettling.’

    Radiator is Faulty

    There are two main reasons why your radiator isn’t heating up: unwanted air or buildup. If your radiator is warm at the bottom, then it may have built-up pressure, which you’ll need to drain out of it or bleed. Radiators typically need a good balance now and then, which includes adjusting the valves so that the other radiators in your house are getting enough water.

    If you try balancing or bleeding your radiator and it’s not fixing the problem, then we recommend contacting a professional. They can help remove any buildup that’s causing the problem.

    Boiler Turns Itself Off

    If your boiler is turning itself off now and then, this could be the result of low water pressure, a lack of water flowing through or even a faulty thermostat. Refer to the above points for the solution to each of these issues, but if none of these work, it’s essential to contact a professional who can correctly diagnose the problem.

    Frozen Pipes

    Boilers need a condensate pipe so that they can get rid of any water that’s become acidic because of the gas. This pipe usually runs into a drain located outside, and in the winter when it’s cold enough it can freeze over.

    If the pipe has frozen over, then you may receive a warning signal. You can thaw out a frozen pipe using a heat pack or a hot water bottle. You can even pour boiling water over it. You may need to reset your boiler once you’ve thawed it out.

    Thermostat is Faulty

    When a thermostat is faulty, it’s going to turn off and on randomly like the pilot light, which we’ll talk about later. This could be a sign that it needs to be replaced. Before you do anything rash, however, it’s important to get to the bottom of the problem so that you don’t end up replacing a pat like the thermostat for no reason. To do this, make sure that the thermostat is on and sitting on the correct settings.

    Another thing to consider here is that your home may be warm, which means the thermostat won’t let the boiler heat your house higher than the temperature you’ve set it at. If this is what’s happening, you can try increasing the temperature gradually until you hit the right one for you and your family.


    Kettling is when buildup or substances like sludge or lime affect the flow of the water within your boiler. If this is the case, then your boiler is going to sound like a kettle boiling. If the water flow has been restricted by this issue, then it could cause the boiler to work overtime and overheat as a result.

    If your boiler is kettling, this means that it’s working harder than it needs to be. This means a bigger bill for you – and it’s also going to wear the boiler out faster. At this point it’s best to get a professional in who can remove any buildup so that your boiler can last longer and not have issues like kettling.

    Pilot Light

    You may know what a pilot light looks like if you’ve had a heater that requires one to warm up. This is the flame that’s responsible for keeping the burner lit. If it’s always burning out, then you may have an issue with the thermocouple. In this scenario, the thermocouple could be stopping the gas from keeping the pilot light lit. There could also be some buildup around the pilot light as well.

    Before you try to relight your pilot light, it’s essential that you make sure there aren’t any issues with the gas that’s supplying it.

    Lack of Hot Water or Heat

    Potential causes of this common problem could be broken airlocks or diaphragms, as well as issues with the water levels and/or the thermostat. The best place to begin with this kind of issue is figuring out whether the issue is with the thermostat or the pressure of the boiler.

    If you think the diaphragm is broken, then you may need to replace it altogether. If it gets to this, then you’ll have to call out a professional who can correctly diagnose the problem and order the right part.

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