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What Are The Most Common Boiler Problems?

Most Common Boiler Problems

With over 20 years of experience being plumbers in Cardiff, there aren’t many boiler problems we haven’t seen before. From leaks, low pressure, unresponsive thermostats and the pilot light going off, we’ve diagnosed and repaired these faults hundreds of times.

Based on our first-hand experience of repairing boilers over the years, below are 10 of the most common boiler problems that we come across:

10 Most Common Boiler Faults

1. Leaking Boiler

A leaking boiler is one of the most frequent problems that we diagnose and repair. Not only does it pose a risk of water damage to the property but it can also lead to malfunctions in the electrical components around the boiler. There can be a number of reasons for a leak such as too much pressure, corroded pipes or tanks, a faulty boiler component or leaks from the seals.

2. Hot Water But No Heating

Believe it or not, when we get called out to carry out a repair, we often come across this issue where it was due to an accidental setting change on a combi boiler.

However, if this isn’t the case, other reasons that cause hot water but no central heating include trapped air in the radiators. If this still isn’t the issue, there may be a fault with a component in the boiler that’ll need investigating.

3. Low Boiler Pressure

Low boiler pressure can lead to cold radiators and a lack of hot water but luckily, it can be easily identified on the boiler display panel. The most common pressure level should be around 1.5 bars but it may vary depending on the manufacturer and model. If you continually get low pressure, this can be due to a leak in the system or a bleeding radiator.

4. Kettling Noise From The Boiler

Boiler kettling is a common issue caused by water heating too quickly and reaching boiling point. Once it has reached boiling point, it’ll generate steam and its the trapped air that produces the distinctive whistling sound.

5. Frozen Condensate Pipe

A frozen condensate pipe is a common problem faced during winter because every condensing boiler has a pipe that transports waste water outside the property. Therefore, if the temperatures drop, the water in the pipe can freeze and this can cause the boiler to shut down.

Luckily, the solution is quite simply and you can simply pour warm water on the pipe that allows the waste water to exit.

6. Boiler Not Responding to Thermostat

A malfunctioning boiler that stops responding to the thermostat can not only be highly frustrating but also prevent you from turning on your central heating.

If you are using a smart thermostat, ensure that your internet is working and that the responder from your thermostat has enough signal to connect to the internet.

7. No Heat & Hot Water

If your boiler stops providing central heating and hot water, it’s a clear indication that there’s something wrong. Some of the possible causes can include the power, gas or water supply has been disconnected, there is high or low water pressure, piping issues or safety features indicating other faults.

8. Boiler Keeps Switching Off

One of the most irritating boiler faults that we come across is when a boiler keeps switching off unexpectedly. Some of the reasons that can cause this include trapped air in the system, low or high water pressures, faulty thermostats, debris or sludge in the pipes and so much more.

9. Interesting Boiler Noises

Your boiler can make a range of noises but if the noises are gurgling, droning, humming or whooshing, it’s likely that you have an issue. Each noise has links to specific faults that we would be able to solve in a matter of minutes.

10. Pilot Light Going Off

For older boilers, pilot lights need to remain lit to light the burner but if any of the components become faulty that controls the pilot light, you’ll have problems.


As you can see from the common boiler problems listed above, some can be solved yourself whilst other need a professional. Therefore, if you want us to repair your boiler, get in touch today to book an appointment. For further information regarding any of the boiler faults listed above, feel free to get in touch.

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180 Ffordd James McGhan, Cardiff, CF11 7JU
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