LP Flex Line Inside the Airstream?

[star kitty]

Hello.

I recently replaced my refrigerator and the old copper tubing for the LP is way too long for my new gas connection.

Local propane store sells both metal and rubber flex lines. This would make my connection very simple

Any thoughts on using either one of these?

[Protagonist]

Originally Posted by star kitty

Hello.

I recently replaced my refrigerator and the old copper tubing for the LP is way too long for my new gas connection.

Local propane store sells both metal and rubber flex lines. This would make my connection very simple

Any thoughts on using either one of these?

If memory serves, RVIA standards call for all propane connections in copper to be double flared. It also calls for no joints inside the trailer except for the final joint between the propane line and the appliance (you can hook the line attached to the appliance to the line attached to the trailer, but no third piece of tubing in between.

My memory might be faulty on this, but I don't think so.

If the existing copper line is too long, you don't need a new one at all. You just need to cut the existing one to fit, and put a new double-flare connector on the new end.

[TG Twinkie]

Rubber would be better than a metal flex line. But it will deteriorate in time. Copper is by far the best.
If you use rubber. Change it out every 5 years or so. Make sure it doesn't contact any sharp edges.


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[idroba]

The general yellow flexible lines used for final connection in homes are not legal in RV's. They flex too much and will crack over time with road vibrations.

Shorten your existing copper gas line. BTW, I have never heard that double flare connections are required in RV's and have never seen them used or made them myself on repairs, although all my experience is with older rigs. I have not had any of the gas connections on my 2014 FC 20 apart to see if they are double flair ones though.

[perryg114]

They make copper flex line that is flared on both ends and I think that is what they are wanting to sell you. I don't like the idea of rubber. There is virtually no pressure on gas lines down stream of the regulator. The main concern is that the tubing does not crack or fall apart due to age. The best way to do this would be to make a new line from the T under the bottom of the trailer up to the connection on the gas valve. The line would be flared at both ends. The copper flex line would be the next best thing.

Perry

[Protagonist]

Originally Posted by idroba

Shorten your existing copper gas line. BTW, I have never heard that double flare connections are required in RV's and have never seen them used or made them myself on repairs, although all my experience is with older rigs. I have not had any of the gas connections on my 2014 FC 20 apart to see if they are double flair ones though.

I knew I had seen it somewhere, so a bit of searching was in order to verify it. Check out Lewster's posts on this thread: http://www.airforums.com/forums/f287...elp-71184.html

He seems pretty adamant about it in that thread, and I've learned to trust Lewster when it comes to RV repair. That's how he makes his living!

[star kitty]

Thanks guys.

I kinda figured you were all gonna say that.

So how do you cut and flare the existing soft copper line down to fit properly? Is this a fitting I can buy at my local propane dealer?

[mimiandrews]

Originally Posted by star kitty

Thanks guys.
So how do you cut and flare the existing soft copper line down to fit properly? Is this a fitting I can buy at my local propane dealer?

You can buy the tools and the fitting at your neighborhood home improvement or hardware store. The skill to use them requires practice, more so the flare tool than the tube cutter. You might be better off finding a mobile RV technician or propane tech to do the job.

If you choose to do it yourself, get hold of some extra copper tubing and keep practicing until you can make a perfect flare. This is your life we're talking about.

[TG Twinkie]

Don't all propane tanks on RV's connect via a rubber hose? The lines into the regulator (high pressure) as well as the line out of the regulator (low pressure).
If you have a grill. It connects via a rubber hose.
If the hose is rated for propane, there should not be a problem.



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[star kitty]

Originally Posted by TG Twinkie

Don't all propane tanks on RV's connect via a rubber hose? The lines into the regulator (high pressure) as well as the line out of the regulator (low pressure).
If you have a grill. It connects via a rubber hose.
If the hose is rated for propane, there should not be a problem.



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From my understanding, they are exterior of the trailer so that is acceptable.

[Wingeezer]

Originally Posted by Protagonist

If memory serves, RVIA standards call for all propane connections in copper to be double flared.


If the existing copper line is too long, you don't need a new one at all. You just need to cut the existing one to fit, and put a new double-flare connector on the new end.

I think you are right about the double flare, but I don't really understand why it would be needed. Maybe I misunderstand the purpose, but I thought it was normally used for high pressure applications - brake lines and other hydraulic applications.

Downstream of the propane regulator I think the normal pressure is only nominally something like 11 inches of water in the propane lines, less than
one half of one psi!

I didn't realize there were special double flare connectors - could well be though.

I have regular flaring and double flaring tools, and the double flare tool just sort of folds the flare back on itself so it becomes double thickness.

Bought the double flaring tool for working on car brake lines.

Brian.

[perryg114]

Seems odd about the double flare. We don't use double flares at NASA and we deal with a lot more high pressure dangerous gasses than what is in an RV. I have heard of it being used on brake lines. We us AN fittings with 37 degree flares. Most of the stuff is stainless steel. I think the real world uses 45 degree flares. I may do every thing in stainless steel at some point from the bottles to the appliances. The copper stuff looks rather sloppy.


Perry

[idroba]

Possibly the double flare is for the lines from the tank to the regulator only. That might make sense as the pressure there can go to over 300 psi. The low side of the regulator has a pressure of only 11" of water, less than half a psi.

Again, I have never seen double flare fittings on any propane low side system in any RV over the years.

[Rolland]

I use the rubber hose from the shutoff to the fridge, because the fridge is moveable, and from the regulator at the tanks to the black pipe. I put a inside shutoff on the point where the black pipe ends and copper tubing goes to each device. (6 shutoff valves inside the trailer) That way you can shut off anything not being used. Everything that is mounted stationary gets single flared copper. Check the system with air pressure and soap before putting gas to it.


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[J. Morgan]

Double flare seems overkill to me, and I can state with certainty that the lines I took out were single flair 45 degree.

I wont use a hose or a flexible metal line in the trailer, and why would I? It is easier just to plumb it in with copper tube.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

[tjdonahoe]

If there were a fire inside, the rubber hose would melt causing a disaster, that is why no rubber gas lines are inside the rv. Also I have never seen or used a double flare on a copper gas line...

[Protagonist]

Time for me to eat crow— please pass the ketchup.

NFPA 1192 (which is the RVIA recreational vehicle standard) says this:

5.3.6.1 Propane tubing joints shall be permitted to be made with a single or double flare of 45 degrees conforming to SAE J533, as recommended by the tubing manufacturer, or by means of listed vibration-resistant fittings, or the joints shall be brazed with a material having a melting point exceeding 1000°F (538°C).

"Single or double flare," it says. Doesn't have to be double flare, despite what Lewster said in that other thread on propane connections. It does pay to go straight to the source sometimes. Double-flare joints are stronger, which is a good thing in a moving trailer, but you can go with single flare if you like, and still be in compliance.

Apologies for the confusion.

[Bigventure]

Hi Pipefitter here,
The copper flex line are now outlawed. They break.
The yellow lines you see are metric stainless steel with metric to standard adapters on them.
Double flare are for brake lines.
Single flare is all you need.
Aircraft and avaition flares are a different angle.

So all you have to do is cut the copper line. Leave it a little long and put a flare on it. I'm sure there has to be a video on flaring a tube.
Put the flare nut on the tube before flaring it.
Project the tube about 1/8 past the vice block. Put the cone part on and turn the handle till it stops. Then remove it. If you mess it up the cone will be to big and the nut won't go over it, if its to small it won't be leak tight. Just cut if off and redo it. A tube cutter with the groves in the wheels is the one for cutting the cone off real close. but you can use a hack saw or just the hack saw blade if it tight.
Anyway I hope I help you.
regards.

[lewster]

Originally Posted by Protagonist

Time for me to eat crow— please pass the ketchup.

NFPA 1192 (which is the RVIA recreational vehicle standard) says this:
"Single or double flare," it says. Doesn't have to be double flare, despite what Lewster said in that other thread on propane connections. It does pay to go straight to the source sometimes. Double-flare joints are stronger, which is a good thing in a moving trailer, but you can go with single flare if you like, and still be in compliance.

Apologies for the confusion.

Just goes to show you when you take the word of your LP instructor at RVIA class. He was pretty adamant about the double flare business, and since that time.....that's the ONLY flare type that I will use on any LP work. Doubles also provide a much softer, more conformable double layer cushion for the nut to seal against the flare. Makes sense to me!

You guys can use whatever.....it's my a$$ on the line any time I touch an LP line, so I err on the safe side.....ALWAYS!

[perryg114]

I don't guess it will hurt anything Lewster. As long as it seals and is safe, that is what matters.

Perry