I've got a bit of 40mm waste before the stack that includes a straight coupler (compression), tee, elbow and shower trap. I want to test all of this is ok, but not sure how to. I could easily check similar in another bathroom where the stack wasn't installed fully and I used a stop end in the partial stack. Here the stack is installed all the way to underground. The pressure will be too much to block of the stack at the bottom. Is there a sensible way to test it just in the 40mm pipework?

 

Photo attached 

Edited August 20, 20251 yr by MortarThePoint

35 minutes ago, MortarThePoint said:

The pressure will be too much to block of the stack at the bottom. 

You are proposing an air pressure test are you not, in which case there will be no problem.

1 hour ago, ProDave said:

You are proposing an air pressure test are you not, in which case there will be no problem.

 

I've got too many branches etc to do an air test I think. What I'd like to do is block the 40mm with something and do a water test as that would test the trap too. Is there something I can use to block the 40mm having been inserted through the tee?

Run some water into the shower tray and get a big towel ready in case you have a gusher.

 

TBH, you'd have to go miles out to get that to leak.

10 minutes ago, Nickfromwales said:

you'd have to go miles out to get that to leak.

 I used the same compression coupler in the other bathroom and it leaked at first so I'm keen to rule that out 

49 minutes ago, MortarThePoint said:

 I used the same compression coupler in the other bathroom and it leaked at first so I'm keen to rule that out 

Ok. With a compression fitting you need to completely disassemble it, and put the removed parts on to each piece of pipe.

 

So you slide the nut on, then the nylon / plastic slip ring (skinny plastic looking washer), and then the conical black rubber washer. 

 

The cone side of the black rubber washer has to be facing the coupler, dito the other side.

 

Push the black rubber ring up the pipe about an inch or so, and then push the coupler on. You may need to give it a wiggle to get the rubber to be as far up the pipe as it needs to be.

 

Slide the nut and the slip ring down to meet the coupler and tighten only hand tight, an angry hand tight (not the angry where you've hit your thumb with a swift hammer blow, but the one where your child has pissed you off and you want to strangle the little bastard, but can't due to recent changes in legislation), and you're good to go.

 

Caveat, if you've bought Chinese fittings off Ali-kebab-express//sweat-shop-R-us, then you're on your own. They prob also sell big towels though...... coincidentally, lol.

 

Are you very sure that you had the rubber conical washers the right way around during previous flood events?

7 hours ago, Nickfromwales said:

Are you very sure that you had the rubber conical washers the right way around during previous flood events?

 

Yes, pretty sure. Also, they're from Wolseley so should be good hopefully.

 

Previous installation only dropped a little when holding a static load.

 

I'm using the compression coupler as a slip coupler having cut out the stop in the middle. I've marked each pipe so I know plenty is in the fitting.