Possible Problem with Shower Waste ?

[WhatNext]

Morning

I have a new mains fed ( unvented cylinder ) shower. The tray has a McAlpine shower waste ( with a chromer domed cover ) and I believe the waste pipe is 40mm.

The pipe work is under concrete so I do not know if if goes direct to the 110mm waste or is T'd in to the 40mm pipe work from the bath and wash hand basiin.

The bathroom is only 2.8mm across and I know that the stack is vented to the openair up at the roof.

When I turn on the shower the water over whelms the waste covering the chrome domed cover for around 30 secs whereupon there is a gurgle and it catches up with the water and from then on no issues keeping up with the flow rate from the shower.

Is this perhaps just a typical problem with mains fed showers and 40mm wastes ? I must admit I wish 50mm had been put in.

Thanks.

 

[Agile]

It sounds like some kind of air lock which once cleared flows fine.

Probably little you can do about it now!

Showers are best plumbed in 50mm mostly because the traps are usually shallow and on a slow incline and easy to be overwelmed by the flow rate!

Tony

 

[longdogs]

In my experience, the chrome cover ALWAYS restricts the waste flow. It looks nice but should be removed when in use.