Vaillant VCW GB 221

20 Nov 2004
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United Kingdom
I would like some advice on a Vaillant vcw gb 221 combi( about 15 years old) please.
The boiler was making a noise and I then noticed there was no pressure indicated. I toppped it up but it went down again. This was repeated a few times until I found the leak. As you look at the boiler it is on the left hand side at the front.
I have discovered this is the DHW heat exchanger. I have researched the price and found prices with and without pipes.
The exchanger I have appears to be plastic and a plumber told me that they have all been changed to stainless as they do not leak.
Do I need the new pipes aswell as he wants to charge me a lot of money to supply and fit a part that I could buy for 25% of his quote.
When looking at it there are about 6 unions and some water top drain. I dont mind paying for a job but i HATE BEING RIPPED OFF.

Any insight into this would be greatly appreciated and then perhaps I could contact another plumber and tell him what I need.

Thanks in anticipation.
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Although it looks straight forward it can rapidly become very involved. :)

You have one of the most complex boilers ever made. Often after replacing the heat exchanger you find the servo valve plays up or the control tubes have blocked so its often best to refurb the whole lot at the same time. Minimum half days work.

There are also some non genuine kits that I've heard don't fit very well. (and you don't necesarily get the diverter disc).

Search the forum and you'll find countless diyers run into trouble doing this repair. ;)
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Part is around £100 retail plus vat for heat exchanger with pipes. anything alot cheaper than this is possible a fake part..

Not a difficult part to fit , but do you know wether you have hybrid pcb or non hybrid do you know how to tell and what to do depending on which board is fitted. Which is why you pay the man

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