DIY - first time for a couple of potable PVC/CPVC repairs


  #1  
Old 03-11-18, 04:25 PM
J
Member
Thread Starter
Join Date: Dec 2006
Location: USA
Posts: 102
Received 2 Upvotes on 2 Posts
DIY - first time for a couple of potable PVC/CPVC repairs

All,

I've got a fair amount of DIY experience with copper and DWV PVC but have never dealt with potable PVC and CPVC. My 10-year-old home has PVC around the well and it transitions to CPVC for the rest of the home.

Two issues I've got:

(1) I have a leak on my UV sanitizing light, right at the threaded fitting where the PVC meets the stainless body of the lamp housing. You can see it wrapped with paper towel in the attached picture. Since it "just appeared", I'm wondering if the UV has adversely affected the PVC in some way; in fact, reading about UV systems, I'm led to believe I should not have plastic connected directly to the lamp housing. You can see the green glow in the pipes from the UV lamp. I'm planning to cut the PVC back aways and sweep a 3/4" corrugated stainless flex pipe between the UV lamp and a new male pipe fitting on the PVC. Couple of questions:
  • The existing piping has either clear primer or no primer. OK to use the Oatey purple primer and medium cement on potable water lines (3/4")? I know PVC for potable is not code in some areas, but apparently it is here.
  • I need to mate the corrugated stainless flex pipe (female) with the stainless UV lamp housing (also female). I'm planning to use a brass hex nipple between the two because it's readily available. Any issues? I believe the swivel fittings on the flex connector are actually nickel coated brass.

(2) I have a couple of "economy" CPVC valves (brand is KBI) around my water heater that won't turn. As I went to try to turn them, one has now developed a very slow drip from the stem. I'm having trouble finding info on these valves on the web. Can anyone tell me if these are serviceable - to either get them to turn or to reseal to stop leaking? I'd hate to have to cut them out to install new ones.

Thanks in advance.
 
Attached Images   
  #2  
Old 03-11-18, 05:18 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 38 Upvotes on 30 Posts
PVC is most assuredly adversely affected by UV light. As far as I know the purple primer is acceptable for potable water but read the can for the best information.

Scratch the swivel fittings to see if they are brass. Most likely the brass nipples will be fine even if the swivels are SS.

Plastic ball valves are almost guaranteed to stick if they are not "exercised" frequently. I won't use them unless it is in a chemical system where brass/bronze cannot be used. If you must use plastic valves I recommend "true union" valves so they can be easily replaced.
 
  #3  
Old 03-15-18, 11:54 AM
J
Member
Thread Starter
Join Date: Dec 2006
Location: USA
Posts: 102
Received 2 Upvotes on 2 Posts
As a follow up, let me share some pictures taken as I'm working on this job today. I don't know if this is a function of the UV lamp deteriorating the PVC fitting, or that the PVC fitting was threaded in to stainless steel, but take a look at what has happened to the threads on the fitting. The source of the leak is obvious. Note: that is not teflon tape on the end of the plastic fitting, it's the threads - so thin that they are unraveling.
 
Attached Images   
  #4  
Old 03-15-18, 12:14 PM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,146
Received 100 Upvotes on 92 Posts
Was there some kind of sealant used on those threads? I think only certain kinds of sealants can be used on plastic threads or it can damage the threads over time. I believe that’s the case.

But I think it’s OK to have male plastic threads into female metal. It’s just that male metal into plastic female can cause the female to split.

Just remembered - I think overtightening can be a problem also with plastic threads, which can damage them. Especially if teflon tape or lubricants are used which will lend itself to overtightening.
 
  #5  
Old 03-15-18, 04:33 PM
Z
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 5,874
Received 372 Upvotes on 332 Posts
UV light does degrade most plastics including PVC. Granted, I've never seen it this significant, but with a 24/7 light, I can see how that would happen over time.

No issue with flex stainless hoses in and out, but as a second option, you can use brass nipples and fittings. Brass piping is expensive, but you'll only need a few fittings so it may be worthwhile to consider. I would do an "L" shape into and out of the device, so there's no way light can reach the PVC.
 
  #6  
Old 03-16-18, 06:41 AM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,146
Received 100 Upvotes on 92 Posts
From the interesting link below:

Recently, one customer wrote to us to ask whether she could use plastic PVC piping in and out of her UV sterilizer. The answer is that yes, you can, but you really should not.
...
https://www.cleanwaterstore.com/blog...r-think-again/
 
  #7  
Old 03-16-18, 06:54 AM
J
Member
Thread Starter
Join Date: Dec 2006
Location: USA
Posts: 102
Received 2 Upvotes on 2 Posts
Originally Posted by zoesdad View Post
Was there some kind of sealant used on those threads? I think only certain kinds of sealants can be used on plastic threads or it can damage the threads over time. I believe thatís the case.

But I think itís OK to have male plastic threads into female metal. Itís just that male metal into plastic female can cause the female to split.

Just remembered - I think overtightening can be a problem also with plastic threads, which can damage them. Especially if teflon tape or lubricants are used which will lend itself to overtightening.
I believe there was some sealant and/or tape on the threads. Though I pulled a similar fitting, with similar sealant/tape from one of the plastic filter housings, and it was pristine. So I think the UV was still at least partly to blame.
 
  #8  
Old 03-16-18, 06:57 AM
J
Member
Thread Starter
Join Date: Dec 2006
Location: USA
Posts: 102
Received 2 Upvotes on 2 Posts
Originally Posted by Zorfdt View Post
UV light does degrade most plastics including PVC. Granted, I've never seen it this significant, but with a 24/7 light, I can see how that would happen over time.

No issue with flex stainless hoses in and out, but as a second option, you can use brass nipples and fittings. Brass piping is expensive, but you'll only need a few fittings so it may be worthwhile to consider. I would do an "L" shape into and out of the device, so there's no way light can reach the PVC.
Thanks. The flex was so easy to do - one brass coupling on the sterilizer, one plastic coupling on the end of the pipe, and the flex between the two. This weekend I plan to re-do the PVC coming from the lower connector as it required a crazy "S" shape in the flex connector due to the short height difference between the two points. Doesn't look as clean as I'd like.
 
  #9  
Old 03-16-18, 07:00 AM
J
Member
Thread Starter
Join Date: Dec 2006
Location: USA
Posts: 102
Received 2 Upvotes on 2 Posts
Originally Posted by zoesdad View Post
From the interesting link below:


...
https://www.cleanwaterstore.com/blog...r-think-again/
That's where I had originally gotten the idea to use the stainless flex connectors (I was not the customer mentioned, just came across the page).
 
  #10  
Old 03-16-18, 08:23 AM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,146
Received 100 Upvotes on 92 Posts
jogordo –

(Wow – that is a big UV filter. mine is puny. but it’s only for 5 gal/min).

I don’t like plastic threads but I have a little CPVC in the basement (but mostly copper). I transitioned from CPVC to brass with adapters (slip CPVC x FIP Brass) so I only have metal to metal threads. But I don’t think there are many PVC to Brass adapters out there- but there are a lot of CPVC to metal adapters. (I guess probably because PVC is not usually used as distribution in the home). However, the link below describes one such adapter for PVC.

The reason I mention this is because if you wanted to you could transition to copper and have MIP copper into your female metal threads – wherever you are using female metal threads. You can then use Teflon tape and Rectorseal #5 on the male metal threads and you would not have any worries about tightening problems or leaks or deterioration of plastic threads in the future.

It looks to me like the adapter would be pretty good. It looks like when you use solvent on the PVC side that connection would be great and there is no way the adapter would leak. Just a thought.

Not trying to make your job more complicated but maybe some food for thought – or something for the future. (but the adapter isn’t cheap).

But it seems to me what you have planned now would work. Good luck!!

https://www.ferguson.com/product/sio...dFamily-245742
 
  #11  
Old 03-16-18, 10:00 AM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,146
Received 100 Upvotes on 92 Posts
Well just noticed. That adapter is 1" or greater and maybe your pipe is 3/4. Could get a little complicated. That might be a problem - bummer!!!

Oh no - forget that, I just saw that it actually can be 3/4. I need more coffee - lol!!
 
  #12  
Old 03-17-18, 05:36 AM
J
Member
Thread Starter
Join Date: Dec 2006
Location: USA
Posts: 102
Received 2 Upvotes on 2 Posts
Thanks for posting the link. I had seen the CPVC-to-stainless and CPVC-to-brass threaded adapters at the big box stores, but like you said, nothing for PVC to metal. I think the brass adapters on the UV lamp and hoses to plastic will probably work OK. Like I said, I'm attributing the failure of the fittings to the UV. I've got a bunch of other threaded plastic adapters (to filter housings in the system) and I don't think a couple more will be a problem. Thanks!
 
  #13  
Old 03-17-18, 02:45 PM
J
Member
Thread Starter
Join Date: Dec 2006
Location: USA
Posts: 102
Received 2 Upvotes on 2 Posts
Figured I'd post pictures of the finished product.

Most PVC fittings from Lowes and local hardware store. Brass fittings from Lowes. Flex connectors are "Eastman" brand from Amazon (24" upper, 15" lower). I liked these connectors better than the ones available at Lowes because they appear to have wider diameter.
 
Attached Images  
  #14  
Old 03-17-18, 04:17 PM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,146
Received 100 Upvotes on 92 Posts
Problem solved. Looks good!!! Let's see the UV get that - lol.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: