Sink fills with water when washing machine empties??? Also very slow to drain...

[BRS82]

Hi,

Hopefully this is an easy fix......

I have moved into a house and some of the work is 'interesting', things you never see when looking originally. Our latest problem is that the sink fills with water when the washing machine empties and also when you empty the adjacent 0.5 sink. The pipework is connected as in the photos dishwasher > 0.5 sink > 1.0 sink this then goes through the wall into a u-bend and into a junction where the washing machine pipe joins it after a u-bend (also the overflow bit from the boiler, or whatever it is) this is all then plumbed into the foul 110mm pipe.

The pipe that goes through the wall is quite high up and I guess this is why there are no traps under the sinks and the u-bend is after the wall. I do intend to drop this down so the fall is greater but it is a 2ft stone wall so this is obviously not an easy task.

Could the issue be that no air can enter the system? Or the very shallow fall on the pipe under the sink.... Or something else?

In the long run, the kitchen will be redone, with a toilet where the washing machine is, would this cause issues if all drianded into this and the toilet?

Thanks in advance

BRS82

 

[snowhead]

You'll probably find it's partially blocked under the sinks where the pipe is near horizontal.
For the time being I'd strip all the waste pipework out and look inside to see if it's blocked and clear it.

 

[SimonG]

The sinks aren't trapped. The horizontal black pipe wants dropping, hell it wants pulling out and redoing from scratch.

 

[BRS82]

Thank you both snowhead and SimonG for the responses. Firstly I will try and see if a new bit of pipe improves the situation in the short term, but I think it is going to need a full strip out and new hole drilled further down (a pain but oh well).

Also if i was going to put a toilet in, would this need to be vented to stop it messing with the kitchen plumbing?

Thanks

BRS

 

[SimonG]

You could fit a short stub stack and put an air admittance valve on it but check other venting first. I.e. do you have a stack that vents to atmosphere?

 

[BRS82]

You could fit a short stub stack and put an air admittance valve on it but check other venting first. I.e. do you have a stack that vents to atmosphere?

Hi,
Yeah there is an outside stack on the other side of the house that is for the upstairs bathroom. Does this cause issues with the AAV?
Thanks
BRS

 

[SimonG]

Hi,
Yeah there is an outside stack on the other side of the house that is for the upstairs bathroom. Does this cause issues with the AAV?
Thanks
BRS

No, as long as you have that one venting to atmosphere you should be fine.

 

[Julian]

the problem is a partially clogged drain after the washing machine