Washing M/C + Dishwasher waste into 1 standpipe?

[mk2phil]

Hi there,

We've just moved into a new huose and have found a problem with the waste pipe for the washing machine and dishwasher. The waste pipe currently has no trap fitted to it and so the smell from the drain is coming back into the kitchen every time we run the tap.

I'm planning on fitting a proper trap and stand pipe, but how can I connect BOTH the waste hoses from the washing m/c and dishwasher into the one stand pipe? The existing pipe has a T fitted giving us 2 standpipes, but I cant see how this can be replicated when there is a trap fitted to the end of the pipe, as the other stand pipe will not have a trap and the same problem will occur. Can I fit a spigot like this: http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=27375&id=12794
but move it to the top of the standpipe so that one waste can enter through the top as normal, then second pipe enters an inch or so down the pipe through the spigot entry?

Would this method cause the standpipe to overflow if they both emptied at the same time?

Using the spigot under the kitchen sink is out becuase its too far away, and I've been reading that the standpipe method is best.

Also, why does the washing m/c waste pipe have to be held high before it enters that standpipe but the dishwasher waste pipe does not?

Thanks guys

 

[breezer]

last question, to prevent syphoning

fit 1 stand pipe fopr each, each with its own trap

dont go near a spiggot

 

[mk2phil]

But I cant do this on the same exit waste pipe can I? I only have 1 waste pipe going through the wall.

 

[HandyHands]

Got a similiar situation that a friend has asked me to look at. They have a single waste pipe running behind the length of the kitchen units and this goes outside (under decking). Into this is connected the sink waste, and a standpipe/trap for a washing machine. They have just purchased a dishwasher to cope with the xmas dishes, and want it plumbing in. I was going to add a further standpipe and trap and connect this further along the waste pipe run.

 

[mk2phil]

I tackled this over the weekend. My local plumbers merchant had the McAlpine fitting in stock where both hoses can be fitted to the top of the original standpipe (VM33 I think). Seems to work fine.

 

[ski2000]

In case anyone else is looking for the fitting mentioned above it is... McAlpine V33WM
"Twin Connector for plumbing two domestic appliance discharge hoses into WM3 Standpipe Trap".

 

[Space cat]

To have two machines pumping simultaneously into a single standpipe is a bit risky. The inertia of the water in the trap may allow the standpipe to flood over before it gets moving. It all depends upon the force of the pumps and the height of the standpipe above its trap.

If you've got the space I would use two standpipes, each with its own trap, and join them together after the traps but before they go out through the wall.