I know this seems to be a well trodden problem, but I can't make sense of why it's happening, or what solution there is for my situation.
I've just finished a complete refit in our bathroom and installed a standard P trap for the bath, an anti siphon bottle trap on the sink and the Mcalpine (ST90CP10-70) shower trap which is very slow to drain with the mushroom cap on, but take it off and the water drains fast. The 40mm waste drops more than enough from the trap and into a 40-60mm reducer/enlarger connected to 60mm waste which, together with waste from the bath and sink, drains down into the main sewer pipe....being a downstairs bathroom with timber floor, this is direct with no access to the pipe outside. Immediately outside, there is a vent pipe, but this is after the drainage goes into the sewer pipe.
I hear mention that with all connections from bath, sink and shower sharing the same waste (as mine does), it can cause vacuum issues and that one solution would be some kind of vent on the shower waste, but as there is no room for this it's not an option.
Is there anything I can do to fix this? It's now been fully tiled, but if need be, I can just about gain access via the next room and scrambling about under the timber flooring, so are there better options for faster shower draining other than this kind of trap?
Thanks.
I've just finished a complete refit in our bathroom and installed a standard P trap for the bath, an anti siphon bottle trap on the sink and the Mcalpine (ST90CP10-70) shower trap which is very slow to drain with the mushroom cap on, but take it off and the water drains fast. The 40mm waste drops more than enough from the trap and into a 40-60mm reducer/enlarger connected to 60mm waste which, together with waste from the bath and sink, drains down into the main sewer pipe....being a downstairs bathroom with timber floor, this is direct with no access to the pipe outside. Immediately outside, there is a vent pipe, but this is after the drainage goes into the sewer pipe.
I hear mention that with all connections from bath, sink and shower sharing the same waste (as mine does), it can cause vacuum issues and that one solution would be some kind of vent on the shower waste, but as there is no room for this it's not an option.
Is there anything I can do to fix this? It's now been fully tiled, but if need be, I can just about gain access via the next room and scrambling about under the timber flooring, so are there better options for faster shower draining other than this kind of trap?
Thanks.