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Discuss Help -What is easiest option to fit double waste under sink ?? in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

Messages
87
Hi All

Attempted to fit a double waste outlet today (w/machine and dishwasher) but failed.

I purchase this from screwfix presuming i could i just swap/convert the current single hose outlet to a double but when i tried i realised it was for 40mm pipe/compression fitting and i could not just unscrew the old one and swap.***.

I then thought no problem i will just remove the current trap with the single hose connection and it all fitted fine BUT the new double outlet has a hole in it and can only be fitted in a vertical position. (Think is stated an 'air break' on the instructions).

What is the easiest option here guys? Do i need to get some form of U trap and purchase 3m of pipe just to use a 4" if that of it to fit this vertically?

Link of new double waste i presumed would just replace existing -


Pics of existing set, where i removed trap on left and fitted above but would leak as it has an 'air break'.

Sink outlet 1.JPGSink outlet 2.jpgSink outlet 3.jpg


Thanks in advance.
 
Messages
87
Update -Could i fit this instead of the current trap on the left?

Cut the outlet pipe that i presume is 40mm and fit the dual outlet i linked above??


Thanks
 
Messages
887
1. The part you have bought is not the right one for use with an existing waste setup.
2. What you really need is a McAlpine SSK1 which has the two spigots for appliance wastes.
3. You currently have a bottle trap. These are generally not recommended for sinks, but are OK for basins. You would need to check you could fit an SSK1 in the space available. You would almost certainly lose some cupboard space.
4. If you wanted to fit a separate stand pipe to take the appliance wastes you could do this and use the part you have bought. However the output from the trap at the base of the stand pipe would need to be taken to a drain outside which would mean drilling the wall.
 
Messages
87
But what is stopping me replacing the trap on the left?
This would provide me with a vertical 40mm (i would have to cut it), then the McApline 40mm hose would just fit on top.
This is a temp fix until new kitchen (will have bigger sink/middle drain area).

Will it work, i know it's not ideal, but as a temp measure, a few weeks, just so the Mrs can use the dishwasher.***

I don't want to be replacing all the pipework at present tbh.

Thanks for the reply.
 
Messages
42
But what is stopping me replacing the trap on the left?
This would provide me with a vertical 40mm (i would have to cut it), then the McApline 40mm hose would just fit on top.
This is a temp fix until new kitchen (will have bigger sink/middle drain area).

Will it work, i know it's not ideal, but as a temp measure, a few weeks, just so the Mrs can use the dishwasher.***

I don't want to be replacing all the pipework at present tbh.

Thanks for the reply.
might be easier to replace bottle trap with a Mcalpine wm11 and a flexcon to reconnect with out going waste
 
Messages
87

What type of flexcon 40mm pipe would i need?

I would fit the WM11 instead of the current bottle trap, cut the existing 40mm waste i presume at the rear/black pipe and use some type of flexcon?

Also the trap on the left would then be redundant i presume?

Would i not need to purchase 3m of pipe as well for the flex to fit? (tiny bit used just to connect to flex to the trap end/flexcon??
Or can you get a flexcon that one end would go into the WM11 (40mm) and the other end has a compression that would go onto black pipe at the rear.***?

Also my current double outlet would just be useless/binned....It's to messy to return i think.

I 'think' i have a 40mm flexcon with a compression the either end in my garage somewhere.***

Thanks
 
Messages
42
What type of flexcon 40mm pipe would i need?

I would fit the WM11 instead of the current bottle trap, cut the existing 40mm waste i presume at the rear/black pipe and use some type of flexcon?

Also the trap on the left would then be redundant i presume?

Would i not need to purchase 3m of pipe as well for the flex to fit? (tiny bit used just to connect to flex to the trap end/flexcon??
Or can you get a flexcon that one end would go into the WM11 (40mm) and the other end has a compression that would go onto black pipe at the rear.***?

Also my current double outlet would just be useless/binned....It's to messy to return i think.

I 'think' i have a 40mm flexcon with a compression the either end in my garage somewhere.***

Thanks
 
Messages
42
you may be able to make up the connection with pipe and fittings but the flexcon option looks like easiest solution in this case. Look on the Mcalpine website to see the range. There are different lengths. You might have to make do with whats easily available where you are.
 
Messages
87
That's what i'm asking/confused about, what flexcon do i need from Screwfix?

What would the set up entail using the WM11?

Is there a flex that will insert direct into the WM11 and the other end has a compression to fit the existing rigid back pipe??

Like a 40mm male end and 40mm compression end flex pipe?

Like this -https://www.screwfix.com/p/floplast-ft40-flexible-waste-pipe-white-40-x-320mm/27334#_=p

Am i thinking along the correct lines here??

Cheers
 
Last edited:
Messages
87
Or this looks better.

Compression on the left would go onto existing black 40mm pipe and other end would just plug into the compression of the WM11??

tThanks
 
Messages
87
Then again looking at the WM11 the output end sits MUCH lower than the bottle trap so if i fitted a flex to connect to the existing pipework thus it would be going uphill??
 

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