Pex and vinyl clamping

[Zoomer]

Hello,
I did search and surely it's an old hot question so sorry for that...

I've had my camper long enough to know about the pex fittings, clamps and tools for it.

I found 1/2" I.D. vinyl hose combined with the pex plumbing and figure that it's not unusual. I've learned that, even though there are cinch clamps on the existing vinyl, that 1/2" cinch clamps for the pex will not fit the vinyl.
I ordered 5/8" cinch clamps and even though they are marked 5/8" I measure over 3/4" I.D. of the clamp and when completely cinched it will easily spin on the hose.

Can someone explain what cinch clamp is needed for the 1/2" I.D./ 5/8" O.D. RV flexible vinyl water hose ?

[TedS]

People have bought cinch clamp kits to find a better size clamp.

[Zoomer]

People have bought cinch clamp kits to find a better size clamp.

Then maybe one will tell me the correct size.

[howson]

Zoomer -- sorry, I can't figure out what's being asked (I'm not the most proficient when it comes to plumbing). Cate&Rob can probably help...

[Zoomer]

Zoomer -- sorry, I can't figure out what's being asked (I'm not the most proficient when it comes to plumbing). Cate&Rob can probably help...

No apology needed howson.

My trailer uses two different types of material for hot and cold water lines. I'm guessing they are the same for other trailers as well.
One type is pex tubing. The other is vinyl hose.
They are both 1/2" but pex is O.D. and vinyl is I.D. - due to that the 1/2" cinch clamp will not fit the vinyl.
Grand Design did use cinch clamps on the vinyl and I'm inquiring what size it is. I assumed when I posted that others had dealt with the issue and would know the size. I'd prefer to purchase only the size needed but so far it seems like purchasing an assortment is the way - which seems to indicate nobody knows which is surprising but Ok by me.

Thanks anyway howson.

[Cate&Rob]

Zoomer
The common sizes for Pex crimp clamps are "nominally" 1/2" and 3/4". Different manufacturers have different unclamped IDs. Some will fit over the soft hose. However . . . a crimped clamp is not the best way to clamp a braided hose on to a fitting. The braided hose will continue to squeeze out from under the clamp over time (which is why most of the original hose connections eventually leak). The best way to retain the hose is with a worm gear clamp . . . which can be tightened when the connection begins to drip leak. Pex clamps on Pex pipe is the "permanent" fix.

Rob

[Zoomer]

Zoomer
The common sizes for Pex crimp clamps are "nominally" 1/2" and 3/4". Different manufacturers have different unclamped IDs. Some will fit over the soft hose. However . . . a crimped clamp is not the best way to clamp a braided hose on to a fitting. The braided hose will continue to squeeze out from under the clamp over time (which is why most of the original hose connections eventually leak). The best way to retain the hose is with a worm gear clamp . . . which can be tightened when the connection begins to drip leak. Pex clamps on Pex pipe is the "permanent" fix.

Rob

So you're saying that the 1/2" I.D. vinyl braided hoses in my 2021 Imagine 22RBE that are clamped with cinch clamps was not done the correct/best way and they should have used worm gear clamps.

Ok - however my question hasn't been answered. "some will fit over soft hose" is much like " get an assortment" .

I thought my question about Grand Designs plumbing of 1/2" vinyl hose with cinch clamps was a simple one: "What size of cinch clamp is on the 1/2" I.D. vinyl hose in my trailer?"

I'm thinking that getting an assortment is the way I'm going to get the answer.

Thanks for the replies.

[Cate&Rob]

So you're saying that the 1/2" I.D. vinyl braided hoses in my 2021 Imagine 22RBE that are clamped with cinch clamps was not done the correct/best way and they should have used worm gear clamps.

This is obviously my opinion and not the perspective of Grand Design. If you are going to try and salvage your leaking soft hose to Pex fitting connections . . . why not use worm gear clamps in place of the failed crimp clamps? Crimp clamps will fail again . . . worm gear clamps can be re-tightened.

Rob

[Zoomer]

This is obviously my opinion and not the perspective of Grand Design. If you are going to try and salvage your leaking soft hose to Pex fitting connections . . . why not use worm gear clamps in place of the failed crimp clamps? Crimp clamps will fail again . . . worm gear clamps can be re-tightened.

Rob

There hasn't been a failure of cinch clamps, pex tubing nor vinyl hose.

There has been a siphon valve failure and Grand Design in all their wisdom installed it inside the little towel rack behind a shower wall where one can only reach it with one hand.
I'm modifying to improve and eliminate the stupidity of their work since I have to deal with the mess.

Anybody with the 22RBE will learn of this when they flood out the area or need to track down the reason for septic tank odor. Fortunately I found it due to leaking water rather than odor - the septic tank has not contained solids.
The siphon valve is also hidden. Not easily seen as some that are located under a sink.

I appreciate your opinion Cate&Rob but the question isn't about my reasons nor is the answer for my question opinions or workarounds as Grand Design knows and uses the correct cinch clamp.

"What size is the cinch clamp Grand Design uses on 1/2" I.D. vinyl hose they install on trailers?".

I do think that the solution is as the first suggestion...get an assortment to get the answer...which has been ordered. Even though I don't need all the clamps - reason for asking- I do think now it's how I'll get the answer.

I do appreciate the time and efforts.

I did just find this old information so thought I'd add it FWIW.

https://www.garagejournal.com/forum/...to-pex.403321/

[Guest]

Zoomer
The common sizes for Pex crimp clamps are "nominally" 1/2" and 3/4". Different manufacturers have different unclamped IDs. Some will fit over the soft hose. However . . . a crimped clamp is not the best way to clamp a braided hose on to a fitting. The braided hose will continue to squeeze out from under the clamp over time (which is why most of the original hose connections eventually leak). The best way to retain the hose is with a worm gear clamp . . . which can be tightened when the connection begins to drip leak. Pex clamps on Pex pipe is the "permanent" fix.

Rob

X2. Vinyl over a barbed fitting would be best with a screw type hose clamp but I have not found a direct PEX to Barb adapter. Seems like a good money making opportunity.

Jim

[TedS]

You might also change the fitting to a barbed end rather than a PEX end and use the screw clamp.

You should get only clear water leak out of the vacuum break valve. If that's any consolation.

[Zoomer]

You might also change the fitting to a barbed end rather than a PEX end and use the screw clamp.

You should get only clear water leak out of the vacuum break valve. If that's any consolation.

Thanks Ted for the suggestion.

The siphon valve -the leaking culprit - is installed by legal requirements. The location and installation are ridiculous and no reason there shouldn't have been long enough hoses to pull the valve out for easy replacement or elimination/relocation of the joining of the two lines. No excuse saving pennies for this ridiculous mess.

Just to share my intensions in case it may help others;

I will replace the inlet fitting for the BT flush with the check valve type. (which I have and easy to obtain)
I will eliminate the siphon valve.
I will run long enough 1/2" vinyl hose to route from inlet fitting,..under the shower and enough to reach out the access grill into the room for ease of clamping/joining of the hoses.
The existing 1/2" vinyl hose connected to the BT for flushing is long enough to be redirected to have access to join with the line from fill inlet.
They will be cinch clamped together - eliminating the siphon valve and placing splice into the hole in floor under the shower so if should ever leak it will not be inside.

Ted that means I'll be eliminating 2 fittings, a siphon valve and the possiblility of the problem every happening again.

Hopefully the correct size will be in the assortment ordered that I should receive tomorrow.

[Guest]

A vinyl hose over a PEX fitting with a cinch (PEX) clamp will eventually let go with 100% certainty. Had one let go under the rig (shooting water into floor opening under the sink) while camping with some nice Grand Design owners. The site was too wet to work on the rig so we had to leave early. We always turn the water pump off when leaving the rig since the OEM vinyl to PEX connections (industry wide issue) can never be trusted.

I ended up extending the PEX into the rig under the sink and found enough fittings to make up the PEX to Barb fittings with service valves added. PITA.

Jim

[Yoda]

People have bought cinch clamp kits to find a better size clamp.

I have probably used thousand of theses installing irrigation systems over the years - usually with HDPE black plastic pipe. A trick I quickly learned is to use 2 cinch clamps per fitting, but turn the cinch portion 180 degrees of the other and space as close to each other as possible. On the two fittings I have replaced they are holding fine - one was the soft pex.

Now I also need to mention that all cinch clamps are not created equal.
This is an example of the ones I used on the trailer. Notice the overlap on the inside so the soft pex does not squeeze through. They will be Pex rated.
https://www.homedepot.com/p/The-Plum...303478006-_-N&

Then there is the typical single band type (cheap)
https://www.amazon.com/Proster-8-8-1...NsaWNrPXRydWU=

Theses leave a weak spot near the clamp nipple. This is the type most used on irrigation.

Hope this helps

Keith

[Zoomer]

A vinyl hose over a PEX fitting with a cinch (PEX) clamp will eventually let go with 100% certainty. Had one let go under the rig (shooting water into floor opening under the sink) while camping with some nice Grand Design owners. The site was too wet to work on the rig so we had to leave early. We always turn the water pump off when leaving the rig since the OEM vinyl to PEX connections (industry wide issue) can never be trusted.

I ended up extending the PEX into the rig under the sink and found enough fittings to make up the PEX to Barb fittings with service valves added. PITA.

Jim

Since purchasing and spending time learning specifics about the trailer the more surprised I am.
Never have had experience with camping trailers and assumed after so many years they'd eliminated "crazy" and "idiocies".I was wrong.

Our pump is on only when water is needed.

I've made many modifications and improvements needed and this is just another one that I'll resolve. A little surprised the question about the size of clamp was such a curve ball but I can hit curve balls so no biggy.

I do appreciate the time folks have spent giving this their attention.

Mike