On Jan 20, 1:29*pm, Onetap wrote:
On Jan 20, 12:05*pm, Mathew Newton wrote:

...there could also be a third - the PRV for the central heating
system (in which case, again, it could be a defective PRV or expansion
vessel).

That one should terminate outside.

Are you sure it has to? Mine doesn't and, sticking my neck out here,
being a new-build one would expect it to comply with the regs.

Mathew