Trailer propane lines - rubber, iron or copper?

[Scrapper]

I don't understand the consensus to not use black pipe. My 832IKBS has bp from the front middle of the frame over to the passenger side and 10' length attached to the I-beam, then across to the drivers side where the furnace and water heater. The stove being in a slide is connected with a rubber hose to a 4-way 'T'. The furnace and wh is connected to the same 4-way 'T' with copper pipe.


BTW, even though it is called black iron pipe it is actually steel. Iron pipe is brittle and the thickness used for gas pipe will shatter from impact. I know this from years of processing iron sewer pipe through the car shredder, it pulverizes to almost a powder. It is also porous and gas leaks through the walls.

[Larry-NC]

Originally Posted by Scrapper

I don't understand the consensus to not use black pipe. My 832IKBS has bp from the front middle of the frame over to the passenger side and 10' length attached to the I-beam, then across to the drivers side where the furnace and water heater. The stove being in a slide is connected with a rubber hose to a 4-way 'T'. The furnace and wh is connected to the same 4-way 'T' with copper pipe.

In the OP's case, all of the appliances are connected to the 4-way T with rubber hose. He was wondering about replacing it with something else.

Two of the connections are more or less straight runs. With black iron pipe, at most two elbows and three pipe segments would be required. The other two have multiple bends as they go through different levels above and below the floor. Trying to do this in rigid pipe would be a nightmare, even if you had your own pipe machine.

Larry

[dward51]

I'm not against using black pipe, it is just copper would be easier to work with and soldered connections less prone to leaking. Repairs would be easier as well. Plus I have the tools to cut, solder and flare the copper where as the black pipe has to be threaded and I don't have that tool. I will either change out the rubber hose connectors at the distribution block to something I can remove later if necessary or change over to copper pipe and bendable copper tubing for the final runs to the appliances.

[TitanMike]

Originally Posted by dward51

Is there any reason not to use flare connections under the trailer belly?

None that I know of. My old 1995 trailer, as well as the 1972 I had before it, used flared connections under the trailer.

Both of them had a piece of black iron pipe that extended from the LPG tank mounting tray back to behind the axles. Wherever there was a connection for an appliance the mfr installed a Tee and a npt/flare brass fitting. Used copper from that connection to the appliance.

Never had a single issue with any of them as long as I owned the trailers (over 40 years in total).

Have already had an issue with a kinked hose and am considering re-plumbing with black iron and copper just like the previous trailers.

[transmission_doctor]

If you install copper lines, USE FLARE FITTINGS ONLY, do NOT solder, repeat do NOT solder fittings, also DO NOT USE compression fittings, only flare fittings are acceptable for use with copper pipe/tubing.

Another poster has suggested CSST, really bad suggestion, the following is straight from the fuel gas code.

"CSST shall not be installed outdoors and shall not be run
underground unless installed in a sleeve or conduit."

[dward51]

Originally Posted by transmission_doctor

If you install copper lines, USE FLARE FITTINGS ONLY, do NOT solder, repeat do NOT solder fittings, also DO NOT USE compression fittings, only flare fittings are acceptable for use with copper pipe/tubing.

So a 3/4" or 1/2" main type L copper line with a soldered on reducer, soldered to 3/8 or 1/2" flexible soft copper before the transition up into the belly and to the appliance end would not work? I know flare is the appliance end of the connection, but what does it matter under the trailer and at the transition to soft? I would think soldered connections would be less likely to leak than any sort of threaded connection (if soldered properly, and yes I know how and know what a cold joint is).

[transmission_doctor]

This is from the fuel gas code.

Any fuel gas lines installed using copper tube must be brazed using a filler metal containing less than 0.05% P (phosphorus) and a melting temperature greater than 1000 degrees F. The only filler metal (trade and industry standard) that contains less than the 0.05% P would be an AWS BAg type alloy (according to the American Welding Society's AWS A5.8 specification). In no case should solder or "soft-solder" be used to join copper tube and fittings in fuel gas systems.

[dward51]

This is a drawing of what I have vs what I'm thinking about if I go with copper. Much cleaner install and easy to work on if something leaks later on or I want to add another appliance line (low pressure grill port?). The appliance ends would remain flair as they currently are. Everything else is outside the trailer underbelly and soldered.

[Larry-NC]

Originally Posted by dward51

So a 3/4" or 1/2" main type L copper line with a soldered on reducer, soldered to 3/8 or 1/2" flexible soft copper before the transition up into the belly and to the appliance end would not work? I know flare is the appliance end of the connection, but what does it matter under the trailer and at the transition to soft? I would think soldered connections would be less likely to leak than any sort of threaded connection (if soldered properly, and yes I know how and know what a cold joint is).

I've looked a lot of residential installations and some trailer installations and I must admit: I've never seen compression fittings or sweat fittings used with gas. Thanks for explaining why.

Now that the subject has come up, one of the alternatives I mentioned involved using threaded unions: unions with 1/4" IP female threads at both ends. Now I'm wondering if those unions are permitted with gas.

Larry

[transmission_doctor]

Again! The fuel gas code DOES NOT PERMIT SOFT SOLDER CONNECTIONS. Flare connections or brazed connections are permitted. Yes you can use a threaded union, but the connections to the copper tubing must be compliant with the fuel gas code, either flared fittings or brazed.

[dward51]

Ok, I can handle brazing. Different filler material and heat source, but I have access (Father in Law is retired Delta Air Lines A&P mechanic and has a well equipped shop with gas welding setup). So assuming we use the correct brazing filler rod on the copper, that is the only "code" issue under the trailer? Correct?

Although this is a low pressure propane system after the pressure regulator. It's going to see 11" WC pressure which is only about 0.4 psi. I know brazing is code for high pressure lines, but I just don't see where it will really matter in a travel trailer low pressure line. The only potential issue I see in making the copper assembly at the FIL shop is getting it back to the trailer as it will be a large assembly. So I either have to transport his setup to the trailer or try brazing with mapp gas and something line Hobart bronze brazing rods (1,300*F).Mapp should get hot enough for that.

I'm thinking the Harbor Freight 91899 torch will work if I use Mapp fuel. It has a wicked pipe solder/brazing tip (screen capture below). Should make it easier to evenly heat the copper pipe. This image is on propane.




One other thing I want to point out. That drawing I uploaded earlier today is incorrect. It showed 5 appliance lines from the distribution block. There is the 1 feeder line and 3 appliance distribution lines. That's what I get for drawing that from memory instead of using the photograph of the distribution block. Here is the correct drawing and the photo of the block. I also corrected the proposed hard copper drawing as well.

[dward51]

Ok, several dozen youtube videos and internet searches later, I'm leaning towards black pipe, with brass flare fittings at the T's. Checked Home Depot and I can get BP in lengths up to 10' already threaded on both ends for a reasonable price. They have a lot of shorter sections, again threaded on both ends. So I should be able to get a workable setup without having to custom cut or thread any pipe.

So BP threaded into pipe couplers with the proper propane rated pipe dope on the threads with 90* elbows and T fittings to basically make my layout in the diagram that I made for the copper. Then brass to flare on the T's and end 90* with flare soft copper that runs to the appliance ends again with flare. Clean and paint the BP with black Rustolem before final install to give extra protection and use rubber lined clamps as hangers to give some slip but still hold in place. In retrospect this is probably the simplest way to go and I should have made this my first choice. I have pipe wrenches and a flaring tool already so in the end it is probably less expensive also and more durable.

Did I miss anything on this option? Yeah, I tend to overthink stuff sometimes.

These!!!! (sample images)

[Larry-NC]

Originally Posted by dward51

Ok, several dozen youtube videos and internet searches later, I'm leaning towards black pipe, with brass flare fittings at the T's. Checked Home Depot and I can get BP in lengths up to 10' already threaded on both ends for a reasonable price. They have a lot of shorter sections, again threaded on both ends. So I should be able to get a workable setup without having to custom cut or thread any pipe.

So BP threaded into pipe couplers with the proper propane rated pipe dope on the threads with 90* elbows and T fittings to basically make my layout in the diagram that I made for the copper. Then brass to flare on the T's and end 90* with flare soft copper that runs to the appliance ends again with flare. Clean and paint the BP with black Rustolem before final install to give extra protection and use rubber lined clamps as hangers to give some slip but still hold in place. In retrospect this is probably the simplest way to go and I should have made this my first choice. I have pipe wrenches and a flaring tool already so in the end it is probably less expensive also and more durable.

Did I miss anything on this option? Yeah, I tend to overthink stuff sometimes.

This seems like a much better approach than trying to braze an assembly in place. I've done a bunch of copper sweat joints in existing walls and ceilings, and even though I place sheet metal guards in place I'm always concerned about setting the place afire. I can just see you on your back under the trailer, setting it on fire.

Larry

[dward51]

Originally Posted by Larry-NC

This seems like a much better approach than trying to braze an assembly in place. I've done a bunch of copper sweat joints in existing walls and ceilings, and even though I place sheet metal guards in place I'm always concerned about setting the place afire. I can just see you on your back under the trailer, setting it on fire.

Larry

Actually either black pipe or copper, I will assemble the underbelly portion "outside" the trailer and slide the completed assembly in and strap to the cross members and frame. The black pipe lets me install the final flare onto the adapter easily under the trailer, where as with brazing, I would have attached a cut to length coil as the main feed line was assembled. Again a plus for black pipe. And now it is supposed to rain for the next 4 to 5 days. Go figure.

[nomad297]

Good luck everybody!

Bruce

[DouglasReid]

Originally Posted by TimVWulp

Never use copper tubing. Propane and copper do not get along with each other. The copper will be damaged by the propane and flake off insde the pipe and plug the tiny orifaces in the system.

That is funny, my last two campers have had copper lines running from the galvanized distribution pipe up to each and every appliance what uses propane.

Other friends have copper pipe feeding an outside propane tank to their house for decades, no problems with the copper flaking and plugging anything.

But, DO NOT use sweated or ferrule connections on copper for gas, it MUST be flare fittings. Otherwise, if the rig were to catch on fire the connections could fail causing a run away gas fire fed by your propane tank until it is empty.

If it were me, Id replace all those rubber lines (which WILL eventually leak) with copper flare fittings.

That way, One access slit under that distribution block will give you access to each and every appliance with an easy quick disconnection should that ever become necessary.

You won't need that torch just a tubing cutter and a flare tool.

[FFred]

'If it were me, Id replace all those rubber lines (which WILL eventually leak) with copper flare fittings.'

The hassle with rubber is not its service life but its ability to take damage that could cut it .

In a chassis where contact with rocks is unlikely , rubber is fine.

The places that do hydraulic hose for trucks and earth movers will usually have USCG approved hose for propane and can install whatever fittings are needed.

I only install hoses with swivel fittings on both ends so the hose can be installed with ease.
Otherwise the entire hose has to be rotated when installing the first end.

[ARICE]

Originally Posted by dward51

Ok, I'm at a snag. I need to get the 5 LP hoses out of the way so I can put a new single piece underbelly back on my Freedom Express 246RKS. The problem is the original lines are all fixed IP fittings into a distribution block in the approximate middle of the camper on the underside. I need to take the lines off to wrangle the big piece of coroplast into place, but those fittings are fixed. So it appears I will need to disconnect the flare end at the individual appliances and then drop the entire line assembly out. Pretty much everything from the LP regulator the each appliance is basically one octopus assembly with fixed fittings. Even if I wanted to slit the belly material to let the lines in to where they transition up to the appliances, I don't think I can get that one piece of coroplast under the trailer as all the other lines are in the way.

Here is the distribution block and those dang fixed connections. As was previously pointed out I will have to unhook the other end of each hose so I can turn the entire hose to unscrew these from the distribution manifold (basically a block with threaded holes in it).



So here is my question. If I have to take this monster of a hose assembly out anyway, why not make what goes back in more user friendly for future repairs, mods, etc... I know eventually I will need to fix something and either the underbelly or a LP line will be in the way.

My last TT was a 1998 model and had black iron pipe under the frame for the LP lines with soft copper to the individual appliances. All the newer ones seem to have these rubber LP lines. Is there any advantage to rubber vs iron pipe or Type L copper (other than to the factory - easier to store and install for them)?

Iron pipe has been around forever and we know it works. Also I've seen TT plumbed entirely with soft copper lines. I'm talking about the stiffer type L 1/2" copper main lines with soft copper 3/8" distribution runs to the appliances. I can solder the fittings and make the flare connections for the appliances. If I break down in East Jesus, Montana, there is probably a hardware store with copper, fittings, a propane torch and solder if I need to repair the LP lines (doubt it will ever happen short of an object bouncing up and damaging a line). If a line is nicked by a road object, I can solder in a splice, etc... You get the idea.

So is there any reason not to use a shorter flexible rubber hose from the LP tanks to the front of the TT and then run hard Type L copper the rest of the way with Copper T & L fittings stepping down to the 3/8" soft copper final run to the appliance.

Or is there some issue I'm not thinking of here?

You could simply cut the hose and install Parker Push Lok fittings rated for LPG (with a swivel end at the block or on the hose) and it would take less than 15 minutes to do.
Weatherhead and Parker Push Lok fittings are the cats meow and rated to 300psi.

[Larry-NC]

Originally Posted by ARICE

You could simply cut the hose and install Parker Push Lok fittings rated for LPG (with a swivel end at the block or on the hose) and it would take less than 15 minutes to do.
Weatherhead and Parker Push Lok fittings are the cats meow and rated to 300psi.

Uh-oh! Looks like you must use the special Parker hose with their fittings.

Larry

[ARICE]

Originally Posted by Larry-NC

Uh-oh! Looks like you must use the special Parker hose with their fittings.

Larry

Uh oh!!! They make adapters