Sink Vent Connection

[nzairforce]

Howdy Everyone,
I am re-doing the walls in my bathroom, and I noticed that one of the threaded parts of the vent from the sink to the main stack was corroded to basically nothing. I removed the rusted threaded portion and ended up cutting the 90 degree fitting as well, as it was corroded to the vent pipe, and there was no way I could have removed it otherwise. My intention was to buy a new threaded section to go into the main stack, and then use an adaptor to connect the main stack to the vent pipe. But, I have now found that the main stack thread is totally rusted and the threads are useless, so I can't fit a new threaded piece. I've attached some photos of my problem, and I was hoping that someone could tell me how I would go about fixing this. Thanks.

 

[nzairforce]

Bump

Bump bitty bump bump. Can anyone help me with this problem?
Any information would be greatly appreciated. Cheers.

 

[Sponsor]

 

[Jadnashua]

The scary part is that if that section was basically toast, the rest may not be far behind...

You could put in very stout supports, cut out the section with the hub, and patch in pvc equivalent, but you'd have to again, really support what is there. They make clamps specifically for this. CI is VERY HEAVY, and if it isn't supported properly will fall and would damage the structure or harm you. When cutting out that section, if it is really worn out and thin, you might just end up crushing it, so that is a big concern, too.

Bump it enough, and one of the pros will give their thoughts.

 

[Winslow]

Howdy Everyone,
I am re-doing the walls in my bathroom, and I noticed that one of the threaded parts of the vent from the sink to the main stack was corroded to basically nothing. I removed the rusted threaded portion and ended up cutting the 90 degree fitting as well, as it was corroded to the vent pipe, and there was no way I could have removed it otherwise. My intention was to buy a new threaded section to go into the main stack, and then use an adaptor to connect the main stack to the vent pipe. But, I have now found that the main stack thread is totally rusted and the threads are useless, so I can't fit a new threaded piece. I've attached some photos of my problem, and I was hoping that someone could tell me how I would go about fixing this. Thanks.

cut out the tee, replace it with a plastic one then tie in the other vent back into it using plastic

 

[hj]

tee

Run a tap into the tee to clean up any remaining threads. It does not have to be water tight since there should not be any water flow past that point unless something was revised after the plumbing was installed. Yours is the classic easy job that has gone bad.

 

[nzairforce]

Tap info

Hi everyone,
Thanks for the replies. I think I will try to re-tap the threads on the CI, before I try to cut anything else out. Does anyone know the correct size and/or thread pitch for the tap required?
I got a 2" x 3" pice of galvanised pipe from HD, which I was going to use to throw in the CI side of things, then use the adaptor to connect to the vent, and it sort of fit in the hole (Just didn't go far due to rusted in thread from the old vent connection!). So should I look online for a 2" tap? I have seen some for sale, but I don't know if they are the correct pitch for the CI pipe.
I'd appreciate any addtional info. Thanks for the help.

 

[nzairforce]

Thread Pitch??

Bump...Bump..
Sorry for the bumps, but I need to start closing up the walls in the bathroom, but can't until i get this issue sorted out. Thanks

 

[Phil H2]

The thread pitch should be listed as NPT.

 

[nzairforce]

Same thread, different questions

Thanx Phil, I'll look out for the right tap for thread pitch.
My next questions invlove vent lines. In the picture 1, you can see 2 galv pipes rising then going right into the main stack, also shown in pic 2 (stack is behind frame). These vents come off the bath drain pipe, (pic 3). As you can see in pic 4, these pipes are full of crude and rust, so i would like to cut them out, and replace with CPVC. In pic 5, on the left, you can see the bath drain coming from the floor above, which i need to tie into the drain.
Questions:
1. Can I cut out the vent pipes, and drain section say in the middle of pic 2, and right hand side of pic 3, put in a rubber adaptor, then run a new drain and vent set up using CPVC? Also, i am thinking of getting rid of the secpnd vent line, as it is not used.
2. How do i tie into the bath drain? If i use the setup proposed above, do i use CPVC p-trap, or can i tie CPVC into a NY or LA brass type trap?
3. I think the drain and vent pipes are 1 1/2 inch dia. What size CPVC would i use to replace? (if possible) same size or 2"?
Looking forward to your words of wisdom. Thanks for all the help so far. Cheers.

 

[Plumber1]

Couldn't say it any better H J................

 

[nzairforce]

Baby on the way! Wife starting to complain

Hi guys,
Sorry for the bump. Just looking for some answers to my previous post. It's taken me a year to sort out the top floor of my house due to work commitments, and now the wifes starting to get antsy due to first baby on the way, and no upstairs bathroom or bedrooms. So if anyone can clear up my last questions so i can finish up, i'd appreciate it. I value all of the information and comments i've received from this forum. Don't think i would have taken on this project otherwise. Thanks.

 

[nzairforce]

Anyone??

Hi there everyone,
I see there are plenty of people looking at this thread, but is there anyone out there that can answer my questions. I don't want to make a mess of this project, so that's why I'm asking for some help. Cheers.

 

[hj]

pipe

The first thing to do is rethink your material. CPVC is not the material to use, even if you could find pipe that size and the proper drainage fittings for it. This application calls for PVC or ABS pipe and fittings.

 

[nzairforce]

Thanks

Hi HJ,
Thanks for the reply!
I wasn't sure if it was CPVC or PVC that should be used in this instance. I guess I was confused with other posts about PVC vs CPVC for water supply lines.
So do I just get a couple of those "no-hub" band connectors to tie into the galvanised side of things, and plumb the vent lines and the tub drain per normal practices?
Should I stick with a PVC p-trap or use the brass type? Or does it not matter the composition of p-trap?
Thanks for all the help everyone. This forum is a great confidence booster for a starter DIY'er like myself.