McAlpine swivel p trap

[Hugh Jaleak]

Might be better to address the cause, rather than the symptoms. What is the issue with the Washing Machine draining that you are currently experiencing?

 

[diy_fun_uk]

Might be better to address the cause, rather than the symptoms. What is the issue with the Washing Machine draining that you are currently experiencing?

tbh there's no issue with the actual machine draining, I think the issue lies in the current plumbing. I've covered it in another thread. Basically the sinks will drain all day long. When machine starts to drain, it's okay for a few secs then starts to back up into the sinks. When the machine stops pumping the water immediately drains. It's like an air lock or something. I want to redirect the machine waste into its own standpipe and trap, leaving the sinks to drain (as they currently do) and hopefully allowing the machine to drain freely.

 

[diy_fun_uk]

Well as promised here's an update. Fitted all the new stuff today, at first hopes were high. Tap on at quite a rate, sink would drain forever and a day. However when I tried filling the sink about 1/4 full and letting water out, it seems to overload the drainage system, the water drains, stops, gurgles, stops then drains fully. I then tried a washing machine drain via the newly installed separate standpipe. Basically it did the same as when connected to the 1.5 kit spigot. It drained okay for a few secs, then you heard a change in tone, at this point I knew it was backing up

So no further forward really. I suspect no matter how it's plumbed under the sink, this issue will remain. Mum's getting a new shower tray fitted soon, it slow drains. The plumber says the flats are known for issues these days (old pipework in the main duct) so he's going to change what he can 'behind the scenes' and he reckons this'll sort it.

So I probably gave myself work (and expense) for nothing however I wanted to give it a go to put my own mind at rest.

I also meant to take a pic of my lash-up but forgot!

 

[Hugh Jaleak]

Sounds like the issue is probably the rate at which the Washing Machine pumps out, is greater than the waste pipe can cope with.

Sink will drain under gravity, so the water will drop as fast as the pipework will allow, whereas the W/M is being pumped out, and the waste cannot cope.

Possibility if an older building, the original sink waste was 32mm copper into a cast stack, the bottleneck where the pipe drops from 40 to 32mm would be enough to cause this issue.

 

[diy_fun_uk]

Sounds like the issue is probably the rate at which the Washing Machine pumps out, is greater than the waste pipe can cope with.

Sink will drain under gravity, so the water will drop as fast as the pipework will allow, whereas the W/M is being pumped out, and the waste cannot cope.

Possibility if an older building, the original sink waste was 32mm copper into a cast stack, the bottleneck where the pipe drops from 40 to 32mm would be enough to cause this issue.

Yeah I reckon it must be something like that. What surprises me though is when I put the tap on near full (great pressure) the sink drains and drains without issue. I wouldn't have thought (maybe wrongly) that the machine is pumping out water at a faster rate, however it's pumping straight into the pipework i.e. not into the sink. As soon as the machine stops pumping, the backed up water clears, as in straight away. Hence me wondering if it was maybe airlocks or something.

The plumber said the pipework in the main duct (where the shower room and kitchen drain into) is often degraded and/or partially blocked, so he'll replace what he can in there. He's never done 'kitchen side' before but says he's done a few shower rooms and it's solved the issue.

I'll update this thread once the work's done cause I know nobody will sleep until I do