On 27/04/2021 21:01, Roger Mills wrote:
I'm planning to refurbish my en-suite bathroom (actually shower room
plus toilet and basin) and would like a shower with a bit of urge -
meaning with a reasonably powerful dual pump to produce a good supply of
(vented) hot and cold stored water. I also want a very low "walk-in"
tray for ease of access as I age. However, I'm wondering whether these
two requirements may be incompatible. Even with a full enclosure, there
needs to be a door - which wouldn't seal well enough to hold water above
tray level.

Are there any rules of thumb for how much flow a shower drain can handle
without flooding the tray? It may be that the only options are either to
go fully "wet-room" with no tray or enclosure, or to settle for a lower
flow rate.

I would like to hear from anyone who has faced similar issues, and to
know what solution they ended up with.

We fitted a shower (with switchable, large, rainfall head and normal,
flexible hose head) into a cubicle with a low tray (about 15mm deep),
although the bottom rail of the door opening does add a further 10mm),
as my wife is disabled and so low is good. The shower is supplied by a
Grundfos pump with a capacity of 50-odd litres per minute at low
pressure, but more like 20 lpm with the back-pressure of the shower.

I fitted a hi-flow waste, rated at 31 lpm. As long as the trap is
cleared of hair every couple of weeks (there are 5 of us), it works
fine. Even if it does start to clog, the water level rises a little, but
that increases the outflow, so it doesn't get too high - and you get a
few days' warning to clean it out.