New professionally installed walk in shower. After being left unused
for a period on running the shower the shower tray fills up with
scummy bubbly water and gets practically to the point of escaping over
the ledge where you walk in. At that point we chicken out and pull out
the big chrome insert that covers the shower drain, and all the water
dissappears in a trice. Putting the chrome cover back in/on and the
water thereafter flows away freely untill the shower has been stopped
for a period (an hour or two?).
I can't find the exact shower waste fitting on the web but it's a
shallow chriomium plated plastic dome about 5" across with what looks
like a 3 sausage-segment air vent holes in the top, about 2cms P.C.D.,
waste shower water is intended to drain away under & around it's
perimeter. 'Cept it doesn't without that bit of persuasion. It seems
it might be at least similar to something called a "Fastflow" waste.
The walk in shower replaced the existing standard bath, but the waste
is perversely at the walk in end and the pipe had to be extended I'd
say the run to the soil stack is a bit over 3 metres and the fall is
less than the depth of the joists with one right angle bend. However
with the domed chrome insert removed it drains OK. If anything has to
be changed under the floor it can't be done, it's all sealed up :-(
I wasn't aware that these shower wastes were such a complicated affair
with concentric cups and sleaves. Exactly what it is all supposed to
do defeats me. Anybody come across anything like this before P.S.E. ?
I suspect that the fall on the waste pipe is inadequate for the length
and diameter, given the waste fitting.
I remember reading somewhere (but can't find the reference now) that
some types of "mushroom" shower drain can capture a bubble of air but
that this goes through to the drain if the flow is fast enough.
Otherwise, the bubble causes the flow to remain restricted. Lifting
off the cap effectively removes this and allows full flow through the
The only two components that can be involved are the waste fitting and
the pipe, but as you say, they are sealed down.
Did the installer do the whole job? If so, or anyway, I would get
him back to fix it. If it does involve ripping the lot up, then I
would expect him to take the cost. He should have done the job
properly in the first place.
Spoken to the fitter, he tells me there is a HepVo valve under the
floor close to the shower. Given that the fall is not great I'm
wondering if the "head", which may only be 4-5 cms, is enough to open
the valve fully until there's a surge caused by lifting the chrome
dome. If left to it's own devices with the shower shut off the water
does run away eventuallty.
I'm homing in on this as an explanation.
On the HepVo website the examples all illustrate a substantial head ,
even with a horizontal installation.
Unfortunately I can't seem to open their PDF design guide. :(
Do these things have a correct and incorrect orientation the fitter
could have got wrong? I've never seen/handled one myself..
Yes. 18 years in the bathroom business.
Absolutely. SWMBO *doesn't like* paddling in a whole load of scummy
water when she's showering. :((
It was OK for me, but most of it is on the web pages anyway by
clicking through the tabs. They make one version intended for
horizontal use that has a fitment to go straight onto the waste
fitting, and is then angled at 87.5 degrees (normal slope).
Yes they do. If he had it the wrong way round it wouldn't work at all
in normal use but will eventually open at 500mm head. If the trap
weren't working properly, you wouldn't be able to get correct results
by removing the cap of the waste.
Then he ought to know what works I would have thought. Is it the
first time he has fitted this waste type I wonder.....
We have a similar experience. As Andy has said it seems to be related
to the design of the drain and apart from regularly dehairing it, there
seems to be no satisfactory answer. I've considered drilling a hole in
the top to see what this does, but I too would like to understand it. In
our case, the run to the main drain is <1M of 40mm pipe, so it's not the
drain blocking. The problem does seem to come and go, but keeping the
trap clear does help.
The chrome thing in my one has a screw height adjustment on its
underside. Hence you can tweak the height above the surrounding tray. I
found my one need raising a mm or two to get suitable flow through it.
Might be worth investigating if yours has the same.
If you run the shower without the chrome insert when the area is empty,
does the water drain away OK - if so, the problem is with the chrome
thing, so I would probably replace it with a normal one.
If not, it's in the pipes. It's possible that the water drains when you
take the chrome thing out, because the reduced resistance allows the
pressure of the water to create a syphon effect, (a bit like a toilet).
I have to do this with my shower because the drain pipes do not have
enough fall, (It's a long story, and will be fixed in the near future).
If this is the case, I would just dump it and not worry how it works <g>
replying to Derek ^, CAROLINE WATSON wrote:
I am having exactly this problem......beautifully tiled bathroom.... I do recall
plumber saying a part was missing from the shower waste pack I bought in b and
q......all vacuum plastic pack sealed and unopened. Since tiler was in a hurry
to start.... a wastevpart..... the outer cup bit... I think..... was installed.
Shower works fine if a human is in it moving about and varying water flowing
into trap. If you go away while waiting for hot water to come through.... tray
becomes flooded. Plunger rectified matter and when chrome lid and bit of white
pipe attached is removed.... drains perfectly fine.
What is wrong then with the obviously incompatible parts?.... come on.... it's
only tubes...air ... water ... and gravity.
Do I drill holes in that white pipe that sinks into the trap? Water drains down
via the rim of the chrome cap part. There are 5 wee air holes in centre of
this... and they are clear of water level..... until backlog starts.... then
Are you talking about the type of shower waste that has a chrome dome
that the water has to flow under? If so I had this problem until someone
on here told me the dome is intended to float up when the water deepens
thus allowing greater flow. I then discovered grit (probably from the
original tiling work) was preventing smooth movement. Once thoroughly
cleaned and the embedded grit polished away it drained perfectly.
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