In article .com,
"Mathew Newton" writes:
A quick question - must the PRV on a sealed CH system be vented
outside?

Yes.

I would've thought so, however the surveyor made no mention of
it on a friend's survey (a full Building Survey I believe) so either he
missed it or is not obliged to check such things?

I would not expect a surveyor to know this, although some might.

As it currently stands the PRV would empty onto the kitchen floor in an
over-pressure condition.

You need to get that fixed. In a worse case failure condition,
that might be ejecting 40kW of steam, and that could seriously
injure or even kill someone in the kitchen.

--
Andrew Gabriel