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Condensing Boilers Unable to Escape Big Freeze

By Laura Elahi on January 4, 2011

In the UK, condensing gas central heating boilers are considered both reliable and energy efficient. Whilst modern condensing boilers can be described accurately in such terms, customers ought to be aware that the latest generations of condensing boiler are not infallible – a point made painfully aware to thousands of householders over Britain’s most recent cold snap.

As temperatures plunged to around -20C in some parts of the UK over the Christmas period, British Gas engineers were called out to fix ailing boilers on an unprecedented scale. British Gas has claimed that its engineers fixed around 100,000 boilers in the six-day period leading to Christmas Eve, by which time the so-called ‘Big Freeze’ had abated.

According to Charlie Mullins, of Pimlico Plumbers, modern condensing boilers are generally efficient and reliable but a plastic pipe used to expel waste water is prone to freezing. Usually situated on an external wall, the pipe carries water produced by the condensation process into drains. Owing to its physical properties and external location, the pipe can freeze in extreme weather conditions, causing the condensing boiler to stall.

Mr Mullins said: “We’ve seen a hell of a lot of this sort of thing this winter and lots of people don’t seem to know much about it. With older boilers you might expect a problem in the cold weather, but when people have spent a lot of money on a new boiler it’s a nasty surprise.”

Mr Mullins added: “There has been more of this, though of course there are more condensing boilers around now. I’m not sure anyone expected to see temperatures like this two years in a row.”

The founder of Pimlico Plumbers stressed that milder winters were probably responsible for fitters paying little attention to how and where such pipes were installed.

Mr Mullins concluded: “Frozen pipes are something you used to see a lot when I was still out and about in the 1970s. But in recent years, particularly in London, it wasn’t so much of a problem. For a modern plumber fitting a boiler it might not be something they think about – whether the pipe is in an exposed spot and likely to freeze.”