How do these two pipes under my sink connect?

scarletjim

Yesterday our kitchen sinks were a bit blocked, so we used a plunger, and drew up some 'mess', so we tried cleaning the pipes in the cupboard under the sink. Only problem is, when we put it back together, it leaks heavily at one point. The are a couple of problems (pictures linked below should help):


https://www.dropbox.com/sh/dkrb0zgfn6utans/AAAARJab_Tof0FX5zaQh8wjra?dl=0


Firstly, there is a thin pipe that goes into a fatter pipe above it (pic 03). The fatter pipe has a thread and a nut with a red plastic washer inside (pic 06), but the thin pipe has no thread, so I don’t understand what the nut is achieving, nor how the thin pipe should be secured to the fatter pipe. If you pull the thin pipe (pic 04), you can pull it down enough to disconnect them (pic 05), even when the nut on the fatter pipe is tightened – so how are they supposed to be secured, and what is the nut actually doing?

Secondly, I found a black rubber washer an inch or so inside the fatter pipe. I assuming it has come off the thin pipe, but I can’t be sure. Where should I position this rubber washer, and which way round? Much like above, I can’t work out how to position it in a way that will actually be of any use! (pic 07 shows it on the thin pipe, but that might be wrong)

Above is a link to an album with 7 pictures, going from a wider pic of the whole system, through to close-ups of the offending parts. If anyone can advise us what to do, we’d be very grateful. (By the way, I’m perfectly happy to call a plumber if that’s what’s needed – but if I simply need to put things together in a certain order and tighten them up, then obviously I’d rather just do that myself). Many thanks. ��

Shaun_of_the_Dead

I'd buy a new trap if it needs ptfe to seal it.

FreeBear

Get rid of the PTFE tape. It has no place on plastic pipes/fittings and is a waste of time.

In one of your images (#7), there is a cone shaped rubber washer. There should also be a rigid washer. Take the "nut" off, slip it over the waste pipe. Then pop in the washer followed by the cone (taper upwards as you have it in pic #7). Push the waste pipe firmly in to the fitting, and do the nut up hand tight.

IF it needs any sealant, use the thinest smear of silicone sealant.

scarletjim

Aha, I didn't realise the nut would come off and fit over the thin pipe - no more leak now, so huge thanks for that. :beer:

The sinks are still taking ages to clear of water, so we failed to solve that problem with our 'cleaning' of a few pipes, but at least we can use the sinks today now (big family meal later today, so would be a pain not to have the sinks).

Anyone know the best way to clear blocked drain pipes, given that we've already tried the plunger and also removed lots of 'mess' from a couple of the pipes (only the couple we could easily access though). Do we need to take the whole thing apart tomorrow? (If so then I think I'd just call a plumber). What about putting caustic soda down the sink, would that destroy the 'mess', or would it destroy the pipes or be otherwise dangerous?

EDIT: Might be worth noting that when we took off the little round cap just to the left of the leaking fixtures, and cleaned in there, after that the water came down and out of that cap hole into a bucket without any apparent blockages - presumably this means the problem is in the pipe going out of the house rather than up to the sink?

By the way, I removed all the PTFE - it was a desperate attempt last night to stop the leak, but (as you both presumably realise) it didn't work.

FreeBear

Be careful taking the fitting off with the black pipe attached - It is (probably) the hose from a washing machine or dishwasher. There could (should) be a non-return valve in there which you do not want to disturb.

Caustic soda down the pipe will do it no harm. Plastic is pretty impervious to that sort of stuff. Using the plunger again may work, but for best effect, get a couple of little helpers to hold damp cloths over the overflows and plug hole in the second sink. Some vigorous plunging should shift the blockage. Put some water in the sink first, then go at it.

You also have what appears to be a "rodding eye" - That white blanking plug just to the right of the blue lever - If it unscrews, you should be able to insert a (very) flexible drain rod to clear what ever is blocking the drain.
Also worth taking the two U shaped bends out and giving them a clean. Not a pleasant job, but it does need doing once in a blue moon.

scarletjim

That's really helpful, thank you. I think we're probably best to leave it now for today, but will have another go tomorrow - firstly with a metal 'snake' thing down that 'rodding eye' (as I suspect the blockage is directly back from there towards the pipe going out of the house), then if that doesn't work try the caustic soda. I'll feed back tomorrow in case you're interested.

southcoastrgi

Your washing machine isn't correctly plumbed in,
The drain pipe isn't a drain pipe that's the one for the water to go in, the drain pipe shouldn't be connected on that tee anyway as there is nothing to stop the smells going back into the machine

scarletjim

Do you mean the very thin black pipe on the right-hand side? If so, it's going to a water softener which was here when we bought the house. Does that change anything?

scarletjim

Quick update - we removed the 'rodding eye' again, and spent an hour or so inserting and removing the 'snake', wiggling it around etc, and got quite a lot of little pieces of debris out. There were no big pieces, and no significant breakthrough point, but nevertheless when I put it all back together, water now seems to be flowing fine with no blockages. Very happy to have fixed it without needing to call anyone out. Thanks for your help (FreeBear in particular).

getmore4less

If the pipes then go outside what can happen is you get a build up of fats as it exits the house(gets worse in cold weather).

The snakes just poke holes through but don't clear, I find a length of garden hoze works better.

scarletjim

Wow that's a good idea, I wouldn't have thought of that, makes sense though.