New boiler - damp issues

19 Jan 2022
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United Kingdom
Hi, I had a new boiler installed about a month ago and I've noticed the external wall seems to constantly damp. The patch seems to be originating at the condensate pipe hole? It seems to be seeping through to the internal wall as I've noticed a couple of small patches of damp under the boiler particular on the opposite side of the wall to the metal prong (pressure relief valve?). Does this look normal or should I call back the plumbers who installed it to have a look? Hope the pic has attached. Thanks


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1. Its not normal.
2. Hard to tell from your photograph whether its from the condensate pipe or the pressure relief pipe.
3. If from the condensate I'd suspect the joint where the condensate from the boiler goes into the larger diameter black pipe.
4. If from the PRV pipe, some sort of boiler fault. Check the boiler pressure, should be between 1.0 and 1.5 bar cold. If greater than 2.5, likely to be leaking. Make sure filling loop is closed.
5. Whatever it is, get the installers back. Unless you have left the filling loop open, its for them to fix and should be no charge.

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