I am installing a shower. As this is on the same waste as the bath and a sink, I want to put in an air admittance valve to prevent gurgling in the trap.
I have a HEPvO valve (its kind of like an elastic bladder in a pipe, which only allows it to flow one way, and which can be fitted horizontally 'inline' as part of the 40mm shower waste outflow piping). I am going to have very poor access (if any at all) under the shower, so I am worried about it getting blocked. For this reason, I might prefer to fit is as per a normal air admittance valve, i.e. run a length of pipe from a T off 40mm shower waste pipe up inside the stud partition and then vent it just to air at the top.
My questions are thus:
1) Am I right to be worried about the HEPvO valve needing access encase it e.g. blocks up with hair and gunk from the shower. 2) Can they be used as a simple air admittance valve, I.e. with no connection at one end. Do they make any noise if fitted like that? I blew down one end and it kind of made a 'raspberry' noise, but that was a pretty hard blow. 4) Would I be able to build it into the stud wall (i.e. no access). I am guessing that if I used it like this (with only air going though it, not waste)it it should work 'for ever'?What'd'y think?
Thanks,
Alasdair