Quick plumbing query

[chris]

We're about to buy a dishwasher.

I have a utility room, with a washing machine in. My father put provisions in (water, power) for us incase we ever wanted a dishwasher or another washing machine in there. There's a drain outside of the utility room, to which a waste pipe runs into - with a standpipe inside. The washing machine waste pipe is pushed into the top of this.

What would be the best way of me adding the dishwasher waste in there? I've read various opinions online, from pushing both waste pipes into the standpipe through to putting on a 'Y' connector to create two standpipes, and then down to drilling through the wall and running a separate waste pipe / standpipe setup for the dishwasher (I don't want to do this).

Thanks.

[Mikey]

You can get a t piece to connect to the stand pipe chris, you don't need an additional u bend as there is already one at the bottom of the stand pipe.

I'll find an image and attach it here for you.

The bottom piece and the spout top right, fit vertically into the stand pipe. City plumbing in Treforest Ind Estate will carry them, can't think of any others closer. 'A washing machine universal fitting.'

They shouldn't be more than £8-10, and probably less.

[chris]

Would I still need the vented hole at the top? I'd rather it was sealed all in to prevent it flooding the floor - unless this would negate the need for it?

I'm guessing that the vent doesn't need to be there, as both appliances will be pumping the water out?

[Mikey]

I think the main purpose of an open vent is air pressure, if you are going to pump water into the pipe it needs to be vented to allow the air out.

Most dishwashers connect into the waste pipe under the sink and are open vented, either through the sink or the overflow if the sink is full. Most washing machines have the hockey stick arrangement that you have now.

I wouldn't worry about the pipe overflowing chris, its highly unlikely unless the pipe further down the line is blocked, in which case its more likely to flow out of the drain than the top of the hockey stick.

[chris]

So that's the T piece on the right hand side? Say dishwasher goes into that via the reducing thingymabob and then the washing machine pipe just in via the open top?

Thinking about it, I wonder if much heat is lost via this open pipe

[Potstubsdustbins]

Chris, the opening at the top of the stand pipe is important. It allows air into the pipe to prevent siphoning when the washing machine empties and prevents the trap seal being broken.

Colin

[chris]

Ok thanks Colin. So the 'T' piece would be the way to go in this circumstance? How is it normally done?

[Potstubsdustbins]

Chris,

Personally if it was me I would cut in a universal swept equal tee just above the existing trap, short run of pipe to a 90` elbow and then form a new upstand clipped back to the wall.

Your local plumbers merchant will have everything you need or look here www.screwfix.com

Colin

[chris]

Thank you