Valliant ecotec 831 plusR1 - Replace boiler or Diverter Valve.

24 Aug 2011
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United Kingdom
I have a Valliant ecotec 831 plusR1 with a leaky diverter valve. If I reduce the heating pressure and leave the heating off the leak stops so I'm still using the boiler in the short term.

(As an aside after 10 years in situ it started leaking - turned out the Condensate hose had popped off. Is that really likely after ten years or is it a symptom of something else?)

I'm in the South East if that's relevant to estimates.

So my options are:
1) New diverter valve - local guy will fit for £250 - is that about right?

2) Replacement.

It's 10 years old & it's had two unrelated faults in 6 months, plus the previous leaks have resulted in some corrosion - is this all a sign it needs to go?
Can I get the same boiler still with identical foot print which should keep disruption to the house and installation cost?
What sort of cost should I expect to fit a new boiler that's a fairly similar fit?
Is there any chance they can reuse the flue, the last fitting wasn't weather proof and gave me a damp problem that took years to diagnose?

Tell me what to do!
Last edited:
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Costs vary up and down the country, so can’t really comment on the £250, but sounds a good price, as your engineer will likely use a merchant, not eBay. Condensate hose could be the known failure type, which would need replacing (Vaillant still provide these foc). For similar footprint, the EcoTEC pro/plus have been discontinued, so depends on a merchant having one in stock, but they have brought out a newer model, believed to be similar footprint. Imo, get the Diverter done, then you could have another few years, you could have a few more faults, but nobody can determine this unfortunately.

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