This is inside the kitchen sink cabinet. I am replacing the drain piping, the hot and cold supply valves, and at the same time, mounting a new 3/16" piece of thin plywood to cover the existing cardboard.

The problem is, the supply piping is CPVC, and connected to a compression valve. I have 9 others to do similar to this.

Once the compression valve was off, I couldn't get the brass ferrule off.



Tried using a plier to rotate off the pipe, didn't work.

Next I have a sleeve puller, but that was designed for copper, so the piece of adapter that goes inside copper tubing didn't fit the smaller ID CPVC, so the sleeve puller didn't work.

Normally I would just use the existing ferrule and nut onto a new valve, but in this case, I want to install a new piece of board on the back side of the sink cabinet, than put in new escutcheons and new valves.

Besides, the ferrule has been chewed on by my plier so much it's deformed. It needs to come out. I am not even sure the CPVC pipe is any good as I might have manipulated it too much as well.



Any suggestions?

My next step will be to use a Dremel to cut across the ferrule and try to split it with a flat head screwdriver.

Is it a bad idea to use a compression stop on CPVC? Is there a better option? Sharkbites?

Dremel is your best friend here. Go super slow, watch closely to make sure the brass chips don't suddenly become CPVC chips. Good quality cut-off wheels are far superior to the brittle super-thin junk, especially when you are working under a cramped sink.

sum... i would just cut the flange off the wall. make the hole you're drilling big enough to slide over the nut and use a split flange to cover the hole.

Packy, the problem is at this point due to my numerous attempt to try to get it off, the brass ferrule has bite marks on it from the plier as I tried to rotate it off the pipe; in the process of doing so the ferrule also bite onto the CPVC as well I can feel with my finger. I don't think the ferrule is round anymore.



Edited 1 times.

sum, i don't have much experience with cpvc. up here north of boston we don't see it at all.

but, since you are covering the wall with plywood, why don't you open up a bigger hole and repipe from a good area of the piping ?

Or cut it right behind the ferrule and use a glue on cpvc stop.

The problem with a glued on stop is in the future if it needs to be replaced you have to cut it shorter again until you are left with no pipe.

Packy, I agree with you.

The only thing is the time constraint. Right now the old countertop and sink have been removed, faucet removed, disposer removed, and so I have some room to do stuff that's impossible once the sink cabinet becomes crowded again.

The countertop guys are coming on Friday, so I am trying to figure out what I can do between now and Friday during the evening hours that I can spare to attack this head on.

I used a Dremel to cut the ferrule off for both the hot and cold side. I did accidentally scored the plastic a little on the cold side. As you can see, as soon as the ferrule was cut through, it popped open with a gap of about 3/16". Even with it cut open it was very difficult to get it off the pipe due to the degree it was strangled. It actually left a narrow neck and I don't think a sleeve puller would have worked anyway.







after thinking about your comment, I went ahead and cut away the back of the cabinet, it was a cardboard anyway. It exposed the CPVC pipes and PVC drains with some of the crumpling sheetrock I pulled off.









I may open a bigger hole tomorrow, but whatever I do need to be wrapped up by Thursday.

Sum, how about cutting the cpvc at the outer edge of the ferrule? The ferrule might slide off. The section of the pipe that the ferrule is on would be buried in the stop and the new ferrule would be on unmolested pipe. The stub is long enough to lose that small amount.

So the question I have is what is the best way to terminate these CPVC pipes if I want some flexibility in replacing the valves in the future?

I don't think compression connections is a good idea. With the sink installed, and a disposer, and faucet with everything hooked up I do not think I can remove a compression valve with a crimped tight ferrule like I was able to do tonight.

A cement on CPVC stop means I will have to cut it shorter next time.

What do you think of a CPVC male adapter, than onto it a 1/2" female threaded stop valve, this will allow the valve to be removed in the future and replaced if necessary. The down side is when the stop is tightened you night end up with the branch at 9'O'clock when your hose is coming in at 3'O'clock.



Another option is to use Sharkbites, which I have always avoided but in this case it's easy and serviceable.

I supposed one way is to tighten a compression valve such that it doesn't strangle the plastic, but I don't I have the skill/experience to do that without it leaking.

I am changing out valves in two other bathrooms in this unit, so 7 more valves to deal with and I want to take the same approach to all.

Sum, screw the adapter into the valve before gluing the adapter to the pipe. You can get your orientation this way.

steve, you are right I could just assemble the valves first then cement them on. That should work unless the threaded connection leaks and I have to tighten it another quarter turn LOL.

anyone know how these fittings are made?



How does the metal and the plastic mate inside? Will the different thermal expansion of the metal vs plastic cause potential leaks especially on the hot side?

There's an o-ring inside to seal the dissimiliar materials. I've seen some that have both an o-ring groove and a separate groove for the CPVC to mould into and retain the 2 parts. The one in the link has combination o-ring and retainer in one groove.
[www.pvcfittingsonline.com]

----

This fitting is available at

[www.plumbingsupply.com]



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steve, thanks for the link that makes sense.

I came across some that looks like this...seems like these are a bad design to avoid, to connect and disconnect one has to put a curved jaw plier on the plastic side to hold it steady to allow a wrench to tighten or loosen the connecting valve. It seems this may stress the plastic and the o-ring. I like those where the exposed metal half has a hex or flats so you can hold the metal side with an adjustable wrench.

Those fittings might have a hex(?) shape on the brass to keep them from spinning in the plastic. I would prefer the stainless that you posted.

I opened up more of the sheetrock behind the cabinet and it's a pretty messy configuration of drains and supply lines in there. I could tell they did some last minute changes the drain and electrical used to be further to the right for some reason they had to really notch out the metal studs for the electrical to come back this way and also reason for that right side drain to be wedged up against the side of the cabinet.







Now I know why the CPVC pipes slid in and out of the wall, I thought they were not secured but they were just that the plastic suspension clamps were cracked when they drove the screws hard with an impact.



What is a better way to attach these, metal straps?

So tonight I cleaned up things a bit and mounted some wood blocking for the plywood piece that is to cover the back side.

Remounted the electrical box and cleaned up the supply lines that were caked with blobs of caulk. New suspension clamps for the stubout but I don't know if these will hold them tight.







The drain for the garbage disposer, now I can see they have a sanitary cross, the right side drain if they had used a street elbow the 1-1/2" pipe would not have been so tight against the right cabinet wall even a slip nut can't be threaded on without removing the fins on the slip nut.

so... use a thinner body metal brass slip nut.

BTW, those plastic hangers are affectionetly known as mickey mouse ears and yes they hold well enough. remember you must allow for expansion.

Packy, the right side drain will not be used. I will use the center drain for both sink (one regular one with disposer). You gave me the idea of using a female adapter to thread onto that male threaded end, and I think I will just cement a short piece of pipe to it and a cleanout adapter with a CO plug and leave it at that. Unless there is a more direct way to close it without using two back to back female fittings.

The old mickey mouse clamps were cracked at the screw holes, I don't know if they were cracked on the day it was installed broken by driving the screw in with an impact driver, or it was cracked later on. Do they make metal versions of these suspension clamps?

sum, i'd be very careful with metal hangers wrapped around plastic pipe. . think abrasion..

you can take a 3/4 or a 1" copper clip and bend the ends inward and give them a twist with some pliers. wrap some rubber (like inertube rubber) around the pipe and fasten that.

Sum, you could use perforated plastic strapping. From the face of the wood strip, over the top, around the back of the pipe and back down the face of the wood strip. This will keep the pipe from pushing back in the wall.

steve, I used new suspension clamps around the CPVC pipes, but Packy's warning about not making them too tight to allow for expansion especially the hot side so I didn't squeeze the clamps all the way. Still have movement if I push in or pull out hard like when putting on a temp Sharkbite cap or valve.





So I am going to try your plastic strap on top of the clamps since I have some left over. I have copper straps too if you think that may be better.

The countertop company was supposed to be here on Friday but called to postpone due to their previous project took longer than anticipated. So now I have the weekend to finish all my stuff in the sink cabinet which is better because I'd rather work in there without the sink easier on my back.

I kept going back and forth on how to terminate those CPVC supply lines, from the way they are strangled I question how reliable another compression connection would be, I have been using sharkbite valves and caps as a temporary measure and that held with no leak so that's an option just sharkbite valves, or go with a CPVCxMIP where the MIP side is metal and I can thread on FIP valves. This is not just the two kitchen valves but also two other bathrooms (one of them has two sinks) so all together I have ten CPVC connections to deal with and I suspect they all have this issue with the compression ferrule strangulation.

I am beginning to warm up to the idea of transitioning to copper piping at the wall. Basically leave say 1.5" of CPVC pipe and cut away the strangled section, then solvent weld onto it a Sioux Chief 643-211 CPVC X MALE SWEAT FITTING ADAPTER:

[www.siouxchief.com]

This gives me 11" of copper tubing to cut back to say 2" or so and I can connect to regular compression valves that I never had an issue removing the ferrule with a sleeve puller.

Do you think this is a good solution?

I know the best solution is to cut the CPVC behind the wall at a vertical position, then transition to an L shaped copper stubout, but the pipes didn't terminate at these locations and the cold side runs up to somewhere else...and I had to close up the wall fast to get ready for their Friday install so I am left with options to modify the stubouts.

Sum, it seems like you've really thought this out, have enough experience and so that sounds like a good plan to me.

Can plastic ferrules be used for CPVC with compression stops? I know that the brass reinforcements will also slide snugly into the end of the CPVC pipe.

This is probably the best option, it gets you out of the plastic onto more durable copper for future servicing.

I got the Sioux Chief transition fitting to do a test. It's an 11" long piece.







I noticed a label on there saying "do not cut CPVC transition fitting".



Since it's a 1/2" CPVC X 1/2" SWT fitting I assume it is because it is designed to be soldered on the other end, and cutting it will melt the plastic and o-ring. I called Sioux Chief and asked if I can cut it to a shorter length if the other end is not to be soldered but a compression joint and they said yes it should work.

So I am going to give this a try and report back.

I am not sure. I have only used plastic ferrules with plastic nuts in smaller sizes like in 1/4" icemaker lines. Don't know about 3/8" or 1/2" connections.

Plastic ferrules only work on pipes soft enough to compress under the low forces exerted by plastic ferrules. Will work on PB lines but CPVC is too hard for the plastic ferrule to bite into and the compression fitting could slide right off under pressure.
Before the advent of the braided supply lines, polybutylene lines were common and I installed a lot of them using plastic ferrules.

OK I did the CPVC to copper transition using the Sioux Chief transition fitting. I cut it down to 2.5", which is about the shortest I feel comfortable because the "neck" of that fitting where it goes from a hub to a pipe has some "rings" around it and I wanted round and smooth copper where the connections will be made.

I cut the CPVC back to about 1.5", completely removed the section that was strangled by the metal ferrule. On goes the escutcheons.





I then cleaned the pipes with emery cloth and solvent welded the copper transition piece on.





I kept water off and waited overnight for the CPVC connections to set before I put on the stop valves because I was worried tightening the valves on the copper end may disturbed the still setting CPVC connections.



Turned water on today and tested it seems to work fine. I will say as I connect the compression stops to the copper section, I still had to be very careful about the plastic connections on the other end.

As I was connecting the stop valves, for the single outlet stop valve it's not a problem, I use two adjustible wrenches one to hold the valve body (which has flats on it) and the other on the nut and I can tighten it quite easily. However, if you look at the last picture above, the hot side serving both the faucet and dishwasher needs a valve with dual outlets/controls. It's really difficult to tighten that one because there isn't a place to put a second wrench on. I had to use a curved jaw plier to clamp it down sideways but that doesn't work really well. Is there a tool I am not aware of that helps in this situation?

I use Pasco Angle On Wrench #4525. It will work for 3/8" compression and 1/2" male iron pipe.

I use it all the time.

Curly, OMG I didn't know such a thing existed. This will make a huge difference in allowing me to hold the valve steady to tighten the other nut! Thank you thank you thank you!!! This forum is great another solution to a problem that's been troubling me for a while. I even removed the handles of these valves just to get a better bite!