John Stumbles wrote:
"Mitch" wrote in message
...
I had a gas safety check on a Bosch 24i combi and the man said that
the pressure relief pipework was sub-standard as it simply runs from
the boiler to the floor with the exit inside rather than an external
exit.

Can someone please tell me what the Building Regs require as I am
thinking of correcting this myself (especially as the main work is
do drill a hole)? EG is it 15mm or 22mm pipe, what are restrictions
on the exit, such as is it downward facing etc etc.



Also where could I read or access these regs?


I don't know which regs cover it - it certainly should be in the
manufacturer's installation instructions - but it should terminate
outside a few inches from, and facing, the ground; so that if/when
the pressure relief valve opens the blast of potentially boiling
water + steam can hit the ground without injuring anyone. 15mm is
generally used.

I even have the original Bosch Installation instructions but they
dont mention this pipework beyond the boiler

Yes, they are normally 15mm. The hole should be drilled so there is a slight
slope downwards from inside to outside.
On the outside its normal for the outlet to be turned back towards the wall
with say a 90 and a 45 degree bends.
This is to avoid scalding anybody who may be near the outlet when the relief
valve lifts.