On Jul 9, 2:37*pm, lardconcepts wrote:
Long story cut short - very old building, second hand kitchen, new
dishwasher.
Without going into details, there are two good reasons for not being
able to run the recommended 32mm standpipe behind the cupboards and
through the 2'6" thick outer stone wall, in which a 23mm hole could
easily be made, but a 32mm one would be "a nightmare" (plus I'd have
to hack holes out of the back of the kitchen units.

One builder and one plumber can't see any way round it other than to
just have a 23mm wastepipe.


Would it help to use two 23mm pips in parallel to give the same flow
area as a 32mm pipe?

Robert