Shower waste problem

[alexbartman]

Am "rennovating" my bathroom - which looks as if Desperate Dan itsel

originally plumbed-in. At the monet, there is a Shower cubible with a 40mm waste teed into th

40mm waste from the bath. This then goes off into the main soil stac (although I can;t yet trace this run as it is under the followboards). At them moment, when the bath is emptied, water comes up through th shower waste - and whilst it's not in itself a major problem, I want t do it right when I put in the new bath/new shower. I plan to keep th existing shower tray but will replace the bath so it is an ideal tim to sort the waste pipes out.

Is this "siphonage" - and if it is, is there a valveoor fitting tha will prevent it Or does anyone have a "top-tip" to solve thi problem.

many thanks

Ale

-- alexbartman

[Vaci]

It's probably not "siphonage" - likely the bathwater just isn't draining fast enough to prevent all the pipes filling (to the brim of the shower waste) with water. I had exactly the same problem caused by bath and shower being connected to the same tee. Fitting a Hepworth "Hepvo" trap to the shower branch solved the problem perfectly.

sell them; part no. 15122, but you should be able to get one from any plumbing supplier.

Vaci