Washing machine draining into sink

[Oliver Payne]

Hi

I've been having some trouble with a kitchen sink draining slowly (from a full sink it seems to drain to half way ok then very slowly for the rest). We have also just had a new washing machine and when this drains it backs up a lot into the kitchen sink.

I thought it would be a blockage so I have cleaned the u-bend and used a rod to clean as much of the pipes as I can (a lot of gook came out but no obvious blockage).

Is it possible there is an air lock? and how would I fix this? I have also checked the overflow pipe isn't blocked and tried plunging a lot. Attached is a photo if this helps.

All help much appreciated

Thanks

Oliver

 

[Iggifer]

Well yes, you have an air lock, but the whole point of a p-trap is that it traps some water in the bend, leaving air either side, so you don't get rank smells. It doesn't take much water pressure to push through 32mm waste though, it's not like it's pressurised.

You are of course, better of asking in the plumbing section, but I reckon you've still got sludge somewhere. Chances are you've just rodded it further down the pipe. Is the outside end of the waste open?

 

[Oliver Payne]

Thanks, it's a second floor flat, and I can't get to any other pipes, I did check the toilet is draining ok and there seems to be no problems there. I had posted in here as I thought it may be linked to the new washing machine, is there any chance sink water is flowing back into the washing machine outlet pipe?

 

[Burnerman]

That's poor routing of the machine waste.....keep it high so that it descends finally into the sink trap. You're asking for all sorts of nasties there, including sink waste entering the washer.
It looks like that's a cleaning point at the swept tee?
John

 

[Oliver Payne]

Thanks John, I did wonder that, stupid question but does the machine waste pipe need to stay high all the way from the washing machine to the sink (not easy as there is a dishwasher in the way) or can I just pin it high under the sink?

 

[DaveHerns]

You need the washing machine drain hose to be as high as possible so as not to connect back flow from the sink

 

[Burnerman]

Yep, avoid loops in the drain pipe if you can......allow the pipe to rise from the back of the machine, and allow a gently descent into the sink drain.
John