Plumbing repair failures

[StevenG]

I have an 87 excella, which has grey plastic plumbing. The firsttrip with it last year I had a leak. I made repairs with pvc, and pvc cement. Now, seems like everywhere I connected the pvc to the grey plastic plumbing, th glue joints are failing. The trailer and plumbing has been used a total of 4 weeks since initial repairs. Now I'm camping, and I've had another failure on one of the original joints. They were all prepared, sealed, and joined correctly. sigh, what am I doing wrong? Of course they'r3e all under the bathroom sink, which is difficult to get to.
Thanks,
Steven

[HowieE]

Cut all of your work out and replace it with new pipe and Sea Tech or Peck fittings. This type of fitting can be removed once in place and makes a good seal in a vibrating atmosphere. They use an O ring as the seal and hold much like a Chinese finger lock.

A bit more pricey but they work. Any big Box Store should have them.

Just make sure when you measure the pipe length you have allowed for the complete insertion into the fitting. The first stop will be the O ring and then if you push harder the pipe will bottom out in the fitting.

[garry]

The gray pipe is PEC and not compatible with PVC cement.

In addition to above "Shark Bite" fittings work well with PEC.

[Gene]

Somewhere I read Shark Bite fittings are fallible. If so, I imagine they would be more so in a trailer.

In any event, starting over seems like a good idea. Either replace all of the original with PEX (more forgiving in freezing weather) or use really good fittings. I doubt there would be a glue compatible with different types of plastic, but perhaps a real plumber would know.

Gene

[easyride]

Originally Posted by garry

The gray pipe is PEC and not compatible with PVC cement.

In addition to above "Shark Bite" fittings work well with PEC.

Gray pipe is poly not pex and will not work with shark bites. Dave

[Ganglin]

Sounds like you used PVC cement on non-PVC pipe as mentioned. If you want to glue it again cut back to unglued sections - use Oatey Purple Primer on the pipe and connectors. Then Oatey Universal Cement (red can) - it works on PVC, CPVC and ABS. A quick vibration resistant fix it to simply make your connections with Fernco Fittings.
fernco, fernco couplings, fernco coupling, flexible pipe connectors, fernco fitting, flexible couplings | Fernco

[TG Twinkie]

Change it out and use "PEX" pipe and "Flair It" fittings. You can get the pipe at the local home improvement store. The "Flair It" fittings are available at www.iplumb.tv
Good Luck

[Jammer]

The gray pipe is not PEX or PEC, it is polybutylene.

Polybutylene pipe cannot be cemented, even with "universal" cements. Originally it would have been joined using crimp fittings that require a special tool. Special compression fittings designed specifically for polybutylene pipe are available, which work well, and which can also serve as transition couplings to pvc or copper.

Sharkbite fittings are not officially listed for polybutylene but some people use them anyway.

Though obsolete now that PEX is available, polybutylene works fine as long as proper fittings are used and temps are kept below 180.

[Ganglin]

Well.... never answer a post while also watching your favorite DIY show. Jammer is correct - common adhesives will not hold long on polybutylene. There is an industrial grade adhesive that can be use but let's not go there...

Jammer - what do you think - these in a tight space like StephenG has:

POLYBUTYLENE repair fittings - PlumbingSupply.com

[easyride]

After seeing the price of the Quest fittings,I`ll stick with the brass fittings and crimp rings. Dave

[Jammer]

Originally Posted by Ganglin

Jammer - what do you think - these in a tight space like StephenG has:

POLYBUTYLENE repair fittings - PlumbingSupply.com

Those actually work pretty well. I used to have PB pipe in a stick house I had, where the water was extremely acid and dissolved metal pipes. The original copper piping had mostly disintegrated after 15 years or so and the previous owner replaced it with PB, and used Qest fittings like those in the page you linked.

They are a little bulky but still work OK in tight spaces because the nuts don't need as much torque as their size suggests, so wrench clearance isn't a big deal.

The brass fittings and crimp rings work fine, too, if you have a crimper, but the crimper costs more than 20-30 fittings so it's not worth it unless you're going to work with a lot of PB.

[StevenG]

Thanks for your replies. I'm home now, and managed to read the first few posts before I lost internet connection on my trip. I had to stop at an RV place to buy a new hitch system (another story, to be posted...lolol) and since the grey plastic was incompatible, I took the service manager out to the AS, and he said pex would work. So I bought what I would need to make the repairs when I got home, since there was no place to buy them here.

Now, my question... WILL pex connections work with this polybutelene (sp?) plumbing? He showed me how to do it, and I cut off a 3" piece of the grey pipe to see if it was a match, it was. And all I do is hand tighten the connections. So, will it work, or am I up the creek?
Thanks!
Steven

[easyride]

If you are using the big bulky Quests fittings,they will work.Dave

[StevenG]

I was able to get out to the AS today. The fittings are PEX. So does that mean they will not work on the polybutylene? and if not, if QUEST fittings are the only ones that will make the connection and seal properly, who sells them?
Thanks!
Steven

[Jammer]

Do a search on qest fittings and you'll get lots of sources.

Polybutylene has a problem with cold flow which PEX does not (on the contrary, the crosslinked properties cause it to return to its manufactured shape over time), which is why I would be concerned about eventual leaks if you use fittings designed for PEX. Who knows, they might work fine, but do you want to experiment with your floor?

[StevenG]

LOLOL no, I don't want to experiment with my floor!
Sorry for the delay, but last week was an exceptionally busy week for me. You folks have been a great help, and I'll proceed with a repair now. Thanks!
Steven