Water appears in the shower when we empty the bath

ise438 · 5 May 2015

Good afternoon,

So basically my shower and bath are connected to the soil stack via the same piece of 40mm pipe, I know this isn't the way to do it but we didn't install it and the soil stack is hard to get to (that's another story).

Anyway when we empty the bath the dirty water appears in the shower (not nice), I've done a little bit of research I think I need either a Non return Valve or and Air admittance valve.

But I am not 100% sure Screw fix sell the NRV - the AAV seem harder to find.

My lame attempt at a drawing to explain..
View media item 94058
Screw Fix NRV
View media item 94056
Ventapipe 25 Air Admittance Valve with integral 1½" Multifit Tee
View media item 94057
If possible would someone be able to tell me which one I should be using?

Also where should I install the extra valve I think it should go on the 40mm pipe between the shower and bath?

Thanks in Advance

Ian...

longdogs · 5 May 2015

The non-return valve fitted in the shower part of the pipe should do the trick. Make sure it's upright and facing the correct way. There may also be a partial blockage where the pipe joins the stack.

muggles · 5 May 2015

You'd be better off with a HepVo waste valve than that NRV, it'll do a better job and will be less likely to block up

longdogs · 5 May 2015

muggles said:
You'd be better off with a HepVo waste valve than that NRV, it'll do a better job and will be less likely to block up

Can I ask how that would stop waste water from the bath travelling up the shower waste - never used one.

Slugbabydotcom · 5 May 2015

Cut the end off a balloon and blow through it........

Now try sucking through it!

It works the same way.

muggles · 6 May 2015

Slugbabydotcom said:
Cut the end off a balloon and blow through it........

Now try sucking through it!

It works the same way.

What he said

They are also useful as AAVs

longdogs · 6 May 2015

Ah yes, I get it now

So the difference being that the NRV has a flap and the HepVO has a membrane. I have used HepVO basin traps but not inline on a waste pipe.

Cheers!

ise438 · 9 May 2015

Thanks - Guys I ended up replace all the waste pipe from the shower as it was fitted with 32mm - So put in 40mm and fitting NRV with access from under the bath

Thanks for help..

Ian.

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Water appears in the shower when we empty the bath

ise438

longdogs

muggles

longdogs

Slugbabydotcom

muggles

longdogs

ise438

DIYnot Local

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