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Which? reveals the most common boiler faults

Learn about boiler faults, and how to avoid them

Boiler controls close-up

We’ve uncovered the best boiler brands that remain fault-free for longer

Which? research reveals that almost half of new gas condensing boilers need at least one repair in their first six years. If you have a less reliable brand, it is even more likely to break down.

A boiler is an impressive piece of kit, they get put through a lot. Even in a moderately busy home, that white box on the wall might be expected to heat up gallons of water to 60 degrees Celsius three or four times a day. 

With so much use, it is no surprise that they develop faults from time to time. And our members have told us that the average cost of getting their boiler repaired is £188 per repair.

However, it isn’t all bad news – more than 60% of the most reliable brand of gas boiler in our annual survey are working fault free after 6 years, so you can minimise the chances of costly repairs by opting for a reliable brand. You can find out what these are by checking out our boiler reviews.

Most common gas boiler faults

The types of faults that can occur with boilers are wide and varied, and you will need a trained professional to diagnose and mend any serious boiler faults.

87% of our members have a gas boiler and the most common faults reported to us are: 

  • Water leaking from within the boiler casing (7%)
  • A frozen condensate run-off pipe (7%)
  • The boiler switching itself off while in operation (5%)
  • Problems with built-in controls (5%).

Most common oil boiler faults

11% of our members own an oil boiler, and our survey data shows us that oil boilers in general are no more or less reliable than gas boilers. The most common faults reported from members who own an oil boiler are:

  • Problems with the burner (9%)
  • Water leaking from the boiler (8%)
  • The boiler keeps switching itself off (7%)
  • Problems with built-in controls (6%).

How can I avoid costly repairs?

The best way to limit the chances of costly boiler repairs is to make sure that when you buy a boiler you opt for the most reliable brand. In our boiler reviews, as well as all of the necessary specification information, we tell you the brand reliability and also the customer score for each boiler brand. This means you can use our research to make sure you choose the best boiler for your needs based on the best and worst brands.

Other than choosing a reliable brand, you can improve your chances of owning a fault-free boiler by having it serviced every year by a trained professional. A good service will highlight any potential problems early and fix them before they become a bigger issue, and potentially prevent any costly collateral damage.

More on this

  • Want to know more about boilers? Head to our boiler features explained
  • After boiler insurance? Check out our boiler servicing contract reviews
  • Learn more about how to choose the best boiler
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