I am looking to replace an old Ideal Mexico boiler on an open vented system.
I have basically decided to go for a condensing boiler and like the look of
the Worcester-Bosch Greenstar 29HE or the Keston Celsius 25.
The main difference I can see between them is that the Keston has a
stainless steel heat exchanger, while the Worcester has aluminium / silicon.
Which of these is likely to have the longest life? (A couple of heating
engineers have said to me that the a condensing boiler will have a shorter
life than a traditional boiler as the condensate gradually corrodes the heat
exchanger. Thus my question as to which material is best.)
Also are there any other factors which would make one a better choice than
Any comments would be appreciated.
This is one of the old wive's tails based on the first generation of
UK produced condensing boilers. Essentially the manufacturers
attempted to adapt existing designs by adding secondary heat
exchangers and failed miserably for the reasons you describe. as a
result, the technology picked up (unjustifiably) a bad reputation in
the conservative trade..
In the rest of Europe, condensing technology has been around for 20
years and most manufacturers are on 4th generation products.
Most of the better ones of these seem to have stainless steel heat
On my own, a MAN Micromat, the heat exchanger is stainless steel and
warrantied, as is the rest of the boiler for 5 years parts and labour.
That doesn't happen if the manufacturer expects a failure after 4
On the other hand, Worcester Bosch have a good reputation with current
products. However, I don't know about the longevity of
aluminium-silicon alloy heat exchangers.
I'd back up Andy's comments. I don't know about the W-B but two
useful (to some people) things about the Celsius are that you do
the air inlet and flue with cheap muPVC (not ordinary uPVC) 50mm
waste pipe rather than expensive flue extensions, and you can
remote wire the panel run/fail lights to another location if the
boiler is in an out-of-sight location
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
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