Understanding the waste stack etc under kitchen sink

supermonkey

Morning All,

A leak from a washing machine y piece has damaged some of the surrounding cupboard, so I am planning on replacing the worst sections.

Unfortunately, this is complicated by the waste pipes. After the trap etc, the waste splits in two, one section goes down through the middle of the cupboard base, and terminates in the waste stack, the other goes towards the back of the cupboard, then extends upwards. It's partially open at the top, suggesting it could be just be a vent, but there's a small pipe in the top of it which goes through the back of the cupboard.

ic

At the top of the pipe labelled "what is this" is a drain slotted in - probably from your washing machine.  At the bottom of that is a clear u bend, so it isn't a vent, its just somewhere to slot in a waste pipe.  Over to the right of the picture on you have another appliance drain connected the alternative way, with a jubilee clip (I think I can make out a label of "dishwasher").  Both achieve the same ends.

FreeBear

Condensate drain from the boiler perhaps ?

tonyh66

That's a mess, the lean on the pipe won't help stopping leaks some of the joints are bent so won't seal properly. The dishwasher is discharging into a filled u bend, so will back up past the joint. What's the vertical white pipe on the right of the picture, and what's the garden hose?

supermonkey

Thanks for replying

Ah right so the pipe on the left is for a waste pipe.

The washing machine/dishwasher wastes are both connected over on the right with ubilee clips, so as suggested, the pipe on left must be from the boiler.

I agree, it is a mess, but the wastes themselves havn't leaked & the lean looks worse because the photo was taken at an angle. The dishwasher waste can't go anywhere else though & there is a decent fall from the waste hose.

Its a 1.5 sink bowl, so vertical pipe front right is from the small bowl (left from main bowl). I sometimes plug in my garden hose there & have a short etension to make it easier to plug in (outside tap seems pointless on a terraced house

Jeepers_Creepers

A close-up photo of the pipe that goes into the top of the LH waste pipe would clarify what it's for. It does look like what FB says - if it's a rigid white pipe of 22mm dia, then it'll almost certainly be the condensate pipe from the boiler.

Where are you suffering the leak from?

supermonkey

Yes, that does make sense. The boiler is to the left in an upper cupboard, so seems about right.

The leak I believe is from the washing machine Y piece which can be easily replaced.

My concern is how I re-build the cabinet with the waste going right through the middle. Am torn between just leaving it as is & having the base board in two sections (with semi circle cut in to allow the pipe) or being brave & adusting the waste pipe work which will likely mean using solvent weld for the first time.

Mickey666

supermonkey said:

Yes, that does make sense. The boiler is to the left in an upper cupboard, so seems about right.

The leak I believe is from the washing machine Y piece which can be easily replaced.

My concern is how I re-build the cabinet with the waste going right through the middle. Am torn between just leaving it as is & having the base board in two sections (with semi circle cut in to allow the pipe) or being brave & adusting the waste pipe work which will likely mean using solvent weld for the first time.

Don't worry about using solvent weld pipe work, is it pretty much foolproof, though I'd stick to compression U-bends for ease of positional adjustment.

Whenever I've tidied up this sort of pipework (some of ours were horrendous!), the most frustrating thing I found was planning what bits of new pipework I needed to buy only to then start work and find I was missing a bit - which is not ideal when it involves a 25 mile round trip to the plumbing merchant!

My solution was to work out what I THOUGHT I needed then buy about twice as much, perhaps more, so that I could be sure of always having the right bend or adapter to hand.  When the job was finished, I'd then return the unwanted items for a refund.

supermonkey

Thanks, it does look straight forward looking at videos, but as you say once its cured there's no room for adjustment.
I may be able to use compression joints under the sink, but if I'm moving the waste pipe further back, I think i'll need to solvent weld where the pipe meets the stack.