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Attach Dishwasher Waste Pipe to Sink Pipe

Postby capo2604 » Sat Dec 17, 2016 7:16 pm


Hopefully someone may be able to help me as I've had conflicting advice on this matter. I've not long moved into an old 1930's house and I've just purchased a dishwasher that will going next to the kitchen sink. However, I've been informed that there is a problem with my existing pipe work under the kitchen sink that will prevent the dishwasher going there. Apparently, I've been told that because the pipe coming from the sink is going upwards that I'll get dishwasher waste coming back up the sink.

However, another person who has given me advice says that I can bypass that piece of piping and attach it to the pipework after where the pipework goes upwards, nearest the wall.

I'm pretty proficient at DIY, but I'm at a loss with this as one as I don't know that much about plumbing. My father in law who is a retired plumber (10 years retired) who says it can't be done without major hassle and says I should move it next to the washing machine and another who is a builder who says it wouldn't take much to get it done without any problems.

I've attached photos in the hope that it will help best describe the situation with the pipes under the sink and finally point me in the right direction of what to do.

Thanks in advance for any help you may be able to offer.
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Simply Build It

Postby greengrass » Wed Dec 21, 2016 1:08 am

Only way cut new hole in the wall behind the trap. remove the existiing bottle trap and replace it with FloPlast Sink & Washing Machine Trap White 40mm (12794) Screwfix see it on their website. Fit the trap mark off the wall behind the trap level with the trap outlet. don't forget the pipe and bends for outside to angle to the drain. You can probably hire a core bit for a drill to cut the hole in the wall needs to be obviously bigger than 40mm , say 50mm tell hire shop what its for.
Does neater hole than hammer and starr core chisel. Just for the record have a look why it was installed uphill?
Hope this helps.Not Rocket science the hard bit is the hole and working under the sink, especially when someone forgets and pours water in the sink with trap off.
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