Insufficient room for washing machine standpipe waste?

[tonton]

This is the waste pipe for my washing machine, a dishwasher also used to be connected. It tees into the horizontal brown push fit waste and then flows to the right (indicated by the brown arrow) and then outside to the shared downpipe.

There's no trap here so I think I have to install one. I don't think there's enough room available for a standpipe waste (a standpipe's vertical section should be >400mm?), so I'll just have to remove the existing connection and connect appliances to the kitchen sink's trap instead? This is ok for one appliance, but if I have two I will have to extend one of the hoses to reach the sink trap, I don't know how feasible that is. Or can I install a shorter standpipe in the current location?

 

[motorbiking]

What is wrong with this:

McAlpine Twin Hose Connector 40mm - Screwfix

Order online at Screwfix.com. For plumbing 2 domestic appliance discharge hoses into a standpipe trap. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

 

[terryplumb]

Without a trap, smells from the drains can enter the appliances/ room via the appliances waste water hose.
Is the waste pipe that goes through the wall connected to a soil and vent stack ?

 

[tonton]

Without a trap, smells from the drains can enter the appliances/ room via the appliances waste water hose.
Is the waste pipe that goes through the wall connected to a soil and vent stack ?

It goes to the right (brown arrow), through the wall and into a shared downpipe (right word?). The kitchens of the other flats above and below me, and the roof's gutters, drain into this shared pipe. It's adjacent to the building's soil and vent stack.

 

[tonton]

What is wrong with this:

McAlpine Twin Hose Connector 40mm - Screwfix

Order online at Screwfix.com. For plumbing 2 domestic appliance discharge hoses into a standpipe trap. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

My understand is that sewer gases would be able to travel up and through that fitting if there is no a trap installed.

 

[CBW]

Could install an upstand one and cut down, or maybe alter the pipework and fit a running trap or waterless trap?

 

[denso13]

Turn the bottom bend down and form a trap with another two bends, will also mean more of a standpipe.

 

[tonton]

Turn the bottom bend down and form a trap with another two bends, will also mean more of a standpipe.

This makes sense. I'll see how much space there is: I might have to reroute the copper supply to get the new waste arrangement to fit and also leave enough room to push the washing machine far enough back under the countertop.

Though plumbing it into the kitchen sink's trap looks like it'll be easier, assuming the appliances' drain hoses will reach.

 

[tonton]

Turn the bottom bend down and form a trap with another two bends, will also mean more of a standpipe.

If I do it this way, the vertical section of the standpipe will be about 250mm max, is this asking for problems?

Even if the standpipe is 'longer' after moving it a bit, it won't be effectively different as the water level in the trap will just fill it up.

 

[denso13]

Will be fine, if it worries you, you could refit what you have now above the new trap.

 

[JohnD]

The kitchens of the other flats above and below me, and the roof's gutters, drain into this shared pipe. It's adjacent to the building's soil and vent stack.

It sounds like the kitchens are connected to the rainwater system.

 

[tonton]

It sounds like the kitchens are connected to the rainwater system.

Yes. But do the two systems join up underground? And therefore it's possible to get sewage smells coming up through a rainwater pipe?

 

[JohnD]

AFAIK rainwater pipes pass through a trap before joining the sewer (on old houses where it is permitted) and are open at the top, and usually an outdoor gully, so are never pressurised with sewer gas.