Pex plumbing leak

[TravelHabit]

OK so it’s been on my To Do list to upgrade the plumbing on my 2022 22RBE; so many stories of leaks and issues. I kept links to what @Cate&Rob had done just for the occasion. Well I’ve had to bump that project to now! I’m finding that GD did use quite a bit of pex (not sure if it is type A or B yet) on some parts of the run and braided tubing on other parts. I had thought much more would be braided. I don’t know if my unit has the better fit flex hose or not (i.e. how does one tell the difference?).

Any thoughts on whether to leave the pex portions alone or to replace everything?

@Cate&Rob I noticed you used type-A pex for flexibility but then used cinch clamps. Any reasons why you didn’t use the expander tool designed for pex-a?

In any case, after removing away the expanding foam at the leak (near the water heater) I took the attached video.

What’s odd is that I’m finding the leak on what appears to be the pex tee. This is unexpected; my plan has been to switch from braid to pex to avoid leaks in the first place! From the video it actually appears the cinching clap is done right. It tuns out this is only on the hot side. If I turn off the valves to/from the water heater the leak stops.

How strongly do folks here feel about ditching the plastic fittings for brass?

In many cases I see GD went from pex to a short run of braided tube to the plumbing fixture. If I cut that out, what is the best way to attach to the fixture (e.g. faucet). The plastic threaded connections seem different than what I have on my home plumbing.

[Cate&Rob]

TravelHabit Just FYI . . . your links are not working. Maybe because you changed the default font? (Based on the moderator comment)

In any case, I have never used the Pex A expansion connections because of the specialty tool required in restricted space and these connections cannot be disassembled.

It is common for Grand Design to use a run of Pex with a soft hose “pigtail” to expedite connection to the faucets. If you want to get rid of the soft hose, simply cut the Pex close to the soft hose and replace with Pex pipe, elbows, etc. As to brass vs plastic fittings . . . either will work . . . use whatever you can source more easily.

To connect to the faucet, you can reuse the existing part (It is a Pex fitting) or obtain a similar new part from any plumbing supply source.

Rob

[TravelHabit]

The key question is how strongly do the folks in the know here feel about removing ALL the soft hose, even the pigtails.

BTW, It doesn't make sense to me that it was somehow easier to put a hose pigtail vs. just using another short pex length; its the same number of crimps and, at least in this location, there were no routing restrictions... The cost difference must be minuscule. I guess I'll have to settle on "it is what it is". On the other hand, just a thought, could it be that having a short pigtail is a better design since the soft hose can absorb road vibrations and movement better than the more rigid pex connection? This would imply it's important to leave braided hose at the fixtures. I'm interested to know what others have done.


P.S.
@Cate&Rob I'm confused as I didn't put any links in the post. I just added attachments: one video and two photos... not sure what to do if they are not coming through

[Country Campers]

I think most here will say to remove all of the flex hose. The reason is that the ID of the hose has not been the right size for a true 1/2" pex fitting that is used in production. The "new" style hose is better but still not correct, IMO. I see no reason why there could not be pex going straight to the fixture, unless there is stress placed on the fixture. If the pex is connected and does not put any stress on the fixture it should be fine. Some have even installed shut off valves before the fixture in case of an issue with the fixture. You could do that an add a braided line from the valve to the fixture, same as the residential set up.

Brian

[TravelHabit]

Thanks. Can you or anyone confirm that the fixture connection is a standard 1/2" MIP? One thought is to replace the braid with a more typical supply line (i.e. HD Brasscraft faucet supply line) and route that to a shutoff connection to pex as you suggest. Just need to confirm what supply line to get. Hate to get the wrong one and find it doesn't connect.

[TravelHabit]

Assuming everything is standard 1/2" MPT/FPT (pretty sure this is same as MIP/FIP), I'm looking at replacing the three valves connected to the water heater for winterizing with two of these Amazon_Valtera_diverter (aternate etrailer link). It appears this will get rid of 10 pex connections and eliminate the middle valve. In particular it gets rid of the one pex connection that now leaks. Any thoughts?

[Scott'n'Wendy]

Just FYI....on a previous brand trailer they ran the pex all the way to the faucet with no soft hose. I never had a plumbing leak in that trailer.

[Cate&Rob]

TravelHabit Your @ tags are what is not working . . . not sure how you are entering these.

WRT the soft hose pigtails at the fixtures . . . the plumbing lines (including soft hose ends) are run before the vanities and fixtures are installed. Because of the soft hose piece, the assembler can grab the hose and fasten it to the fixture without needing to cut additional Pex and crimp the fittings. This is a big time saver on the assembly line.

My plumbing system is 100% Pex with no leaks for several years and thousands of miles.

Rob

[Lonestar]

I have yet to have a PEX to soft hose leak, but I bought some of the PEX to soft hose adapters just in case. I think this might be a cheap, quick, easy repair vs. replacing with PEX. I am carrying PEX tubing, fittings, and tools as well (just in case).

[Cate&Rob]

Lonestar

And it is because you have the spare parts ready . . . you may never have a leak . It is some kind of unwritten insurance policy.

Rob

[Lonestar]

Lonestar

And it is because you have the spare parts ready . . . you may never have a leak . It is some kind of unwritten insurance policy.

Rob

You got that right! I guess we could keep adding to our inventory but at some point the "suspension part" of that unwritten insurance policy is gonna crash.

[rebcorellc]

I think most here will say to remove all of the flex hose. The reason is that the ID of the hose has not been the right size for a true 1/2" pex fitting that is used in production. The "new" style hose is better but still not correct, IMO. I see no reason why there could not be pex going straight to the fixture, unless there is stress placed on the fixture. If the pex is connected and does not put any stress on the fixture it should be fine. Some have even installed shut off valves before the fixture in case of an issue with the fixture. You could do that an add a braided line from the valve to the fixture, same as the residential set up.

Brian

I'm a total newbie - so apologies up-front. We are purchasing a 2024 Imagine XLS 23LDE and the ONLY real concern I have with Grand Design are these on-going plumbing issues where they connect the PEX to that braided soft hose incorrectly. My understanding is that this is NOT up to any kid of industry code. You mentioned a "new" style hose they are using. Is this new for 2024? Or - does anyone know if Grand Design has made changes to how they install and connect their plumbing for the 2024 model year - or what changes they've made to address these connections? Thank you all in advance.

[Cate&Rob]

rebcorellc

Grand Design (and all towable RV manufacturers) build to a “code” defined by their own organization. RVIA. Recreational Vehicle Industry Association. This code allows soft hose crimped to Pex fittings. This would not be allowed by any other residential or motor vehicle building code.

Rob

[rebcorellc]

Cate&Rob Thanks Rob! It seems like RVIA needs to revisit their codes.....I hope they don't simply mirror the lowest common money/time-saving practices of their member manufacturers. I'm hoping the '24 models reflect some correction to this problem - though so far I haven't found any information that would suggest this.

[TedS]

You would think with the rv industry purchase power it could get a pex straight rib barb to conical hose barb fitting made by a fitting manufacturer. It seems the volume would make the manufacture of the fitting attractive. It's just lathe or screw machine work.