Washing machine emptying into sink and vice versa

Vejovis

I have long suspected that the sink has been draining into the washer, since we got a new kitchen put in last year. The builder came back and adjusted the plumbing, but it kept happening, but only on a minor scale.

Then the sink started draining really slowly, so I put down some Mr Muscle Foaming drain cleaner. That didn't help, so I took the trap apart, but there was no blockage.

Then today I noticed the sink was full just after the washer drained, and it was full of washing machine water. Then when the washer stopped spinning, the water drained from the sink, and when I opened the washer door, it'd gone back in there.

This is the set up I have (sorry it's a bit blurred), the washing machine hose is attached where the black arrow is.

Can anyone shed any light, or offer any advice. I've rang the builder a few times, but with no luck, and I'd rather not have to shell out for a plumber.

Browntoa

Can't see the black arrow ?

Is the washing machine feeding in from the left ? Or the right

To me it looks like the mid section between the two is too low and fills with water before it can drain into the waste outlet pipe which seems to be on the right ? And above the mid piece

Vejovis

The washing machine is coming from the right, the white pipe on the left is the overflow pipe from the sink.

Edit sorry yes that is the waste pipe going off to the right.

Vejovis

Is this sort of thing likely to help?

http://www.screwfix.com/p/sink-washing-machine-trap-40mm/12794

WestonDave

I would personally try to find a way to join the washing machine outlet in to where the overflow joins.

The problems with your current set up as that your "U" bend is very shallow, and if you look on the right, the high point of the washing machine outlet is very near the height that the main outlet heads to the drain. This means its too easy for water to go over the hump into the washing machine rather than over the hump where it is supposed to go.

newbie1980

maybe getting a plumber to do the set up correctly will be best option

if it was just a builder he may think thats ok but the set up looks totally wrong

at the least a proper u bend is needed and the washer fitted to that

jbainbridge

It's difficult to see from the picture - how high does the washing machine waste go?

And is it possible to raise part of it to resist the flow of water? A loop going ABOVE the waste pipe should help things.

If it is just going down, it will be natural for water from the 'trap' to flow back to the washing machine. I can see where the builder is coming from - it _should_ work. Though the Screwfix link (from Verjovis) shows the correct fitting

Vejovis

I've tried a couple of different photos and remembered the flash this time

Do these make it any easier to see?

muckybutt

That whole set up is completely wrong !

For starters I would install a proper trap http://www.screwfix.com/p/mcalpine-appliance-trap-40mm-white/81714 the washer hose needs to be higher than what it is too, at the moment with it being lower than the outlet from the sink water is going to go down there as it offers the least resistance to flow.

Raise the hose up for starters then replace the trap and pipework, the builder that did that is a cowboy !

Vejovis

Looks like a trip to Screwfix is in order tomorrow.

Thanks for the help guys

force_ten

during my days as a domestic appliance repair engineer i used to hate the under sink appliance traps they caused all sorts of problems just as you describe with foul water draining into the machine

in the ideal world a washing machine or a dishwasher should be fitted to one of these


www.screwfix.com/p/washing-machine-trap-40mm

using one of those is what most machine suppliers recommend but it would require a bit more work to fit one

fitting one of the other under sink traps linked above will be better than you have got