shower draining poor

[maria11]

Hi
I am currently having a new shower fitted,it was connected to the pipe/drain today,it does not seem to drain well and when I looked there is water in the pipe leading from the trap,about 1 cm ish.I had expected ot to drain completely except for the sump in the trap.The plummer is talking about putting a regulator on to reduce the flow rate from the h/c ..should I be concerned about the gradient in the pipe work?
Thanks for any advice you can give.
Maria

 

[longdogs]

You are correct in thinking that the water should drain completely except for the trap itself. Altering the flow will not get rid of the water sitting in the pipe.

It's likely that the pipe will be prone to blockages after a couple of years due to soap/grease build up.

 

[Armo74]

I would certainly be questioning the fall on the wastepipe. Will only lead to future problems,What type of shower is it?

 

[maria11]

it is a thermostatic valve off mains,new pressurized Valliant eco direct feed boiler,thanks for your reply.
Maria

 

[Jamesie]

As mentioned, fall of waste pipe. Also size of waste, should be 1 1/2", if you can see the waste pipe, check its not same size as your wash basin. When i ripped a bathroom out recently there was inch and half from bath trap, with a reducer to inch and a quarter, which was tee'd with wash basin to soil stack.

 

[judder]

Sorry for jumping in here, but I have the same problem. I've just stuck a spirit level on my waste pipe and found that it the plumber laid it just off horizontal (the bubble in the level is only slightly off centre). How much fall in the waste pipe do you recommend?

 

[Jamesie]

Im not sure what the minimum figure is, 1 for the pro's. i judge it by eye personally.

 

[Armo74]

The fall should be roughly upto 18mm per metre length of wastepipe.

 

[longdogs]

Another thought. assuming that you have a 40mm (1 1/2") waste pipe, changing the trap may help. I don't know which type you have but some of these so called 'fast flow' traps reduce down to 32mm before reverting back to 40mm (bizarre)