Washing machine problem

[shellt]

My washing machine drains, but fills the kitchen sink and then drains straight back into the washing machine. I wonder if it could be the washing machine itself that's the problem, or maybe a blocked pipe in the kitchen??

[trendypaul]

Sounds like the problem is with the connection to the waste pipe under the sink, rather than the washing machine.

[brachiopod]

Your washing machine appears to be 'back-syphoning'.

A

[brachiopod]

Sorry, I'll start again ( a little 16 month old is pressing keyboard buttons again)

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Your washing machine appears to be 'back syphoning'.

A partial blockage in your sink's waste pipe is causing slow drainage and as a result, your sink fills up when the washing machine pumps out the waste water.

The waste pipe outlet from your washing machine is now submerged. Since most washing machines do not have non-return valves, the next time it tries to 'pump-out' it will instead 'suck-back' the waste water from the sink. This is known as back-syphonage.

(Effectively, the waste water in the sink is higher than  the washer, and connected by a tube full of water, so it will syphon back to the lower potential, ie the washer!)

Dismantle and clean the trap under the sink. Re-assemble and use either caustic soda or one of those proprietery brands of 'sink and drain cleaner' (the foaming type things - haven't tried them myself - I just pour caustic soda down the plug - but be careful!)

Yor sink should now drain freely. If your washing machine outlet is plumbed in to the waste pipe under the sink (rather than hanging over it) you can try putting an 'anti-syphon loop' in if you have sufficient length of hose. This just means raising a loop of the hose above the level of the waste pipe connection to help prevent back-syphonage.

Good luck!