Copper Pipe Size?

[jr3149]

Hi,
I am planning on replacing the copper LP lines on my Trade Wind and I am wondering about appropriate size of the piping i should use. I have read from other forums that I should use type K copper.
My questions are:
What size ID / OD copper should i use from the regulators to the point of use?
Should I use different sizes from the main line to the T/Valves and from the Valves to the inside of trailer (where they attach to the appliance?)
and Lastly - is is possible to use a flexible hose type of attachment for the point of interconnection to the appliance? (i was thinking that this would prevent kinks in the future.

Can anyone shed some light on this subject?

[InsideOut]

You may want to consider using PEX & Sharkbite fittings...it's a lot easier to work with in a retrofit situation ~ we did in our '56 and are real happy with the results.

Shari

[clancy_boy]

I think the OP is talking LP (PROPANE) lines.

Check with trailer repair locations, LP systems present a whole lot of issues with replacment for the DIY people. Flex lines usually have a label that states on them not to be used in a high vibration location - once bent they don't want to be moved - that really is not the situation in a RV. There are rules on making connections internal to the RV, and what types and locations of valves. In general there should not be any concealed connections in the walls or under the floor - just straight pipe.

[idroba]

If you have the original copper pipe LP gas system, just replace it, like for like. That way you will know it will work just fine.

On flexible lines to the final use point: I am not sure there is any advantage doing that, but do not use the corrugated metal ones that are used on home interior hookups, like to a range or water heater. They are not legal in RV's, and do not take the constant flexing that they would encounter in an RV. Possibly you could consider rubber lines for the final connection, but again, I am not sure there is any advantage over solid copper with flair fittings, as was done at the factory.

Other than physical damage and two cracked flair nut fittings, I have seen very few problems with the copper gas lines that were the original equipment on any of the 17 or so AS products I have had over the past 33 years.

[cliffcharb]

as stated by idroba, just replace with the same size. When we re-did our trailer i believe we used 1/2" for the main line and 1/4" going into the trailer. You can buy the copper tubing from HD or Lowes. The only flexible line I used was to hook to the regulator. There really is no need for flexible line in the trailer. Make sure you flare all of your fitting, dont use compression fittings.

[InsideOut]

Originally Posted by clancy_boy

I think the OP is talking LP (PROPANE) lines.

Oops, sorry!

Shari

[edglenn]

Good question. It comes up a LOT. I had the same question myself when I started. Check throught the archives for more info.
I'll recap what I think I know (others please chime in):
Propane is VERY explosive if it leaks, so don't cut corners. Don't risk it.
Eliminate all extra shut-offs, T's, and flexible connections inside the trailer.
All propane lines need to be routed outside (underneath) the trailer, and penetrate through the floor directly to the appliance.
The main line (vintage trailers, at least) are 5/8" or 1/2" from the LP tank regulator. The secondary lines branching out are 3/8".
Install the petcock shut-off's underneath, at the main line or where they penetrate the undercarriage.
Type "K" is thick walled copper pipe, listed for propane. Lowes and Home Depot usually don't carry it. They only carry "L" or "M" for water and refrigeration.
Use only flared fittings, so you'll need to purchase a flaring tool.
Too much argument about single-flared or double-flared due to code changes. Take it for what it's worth.
What I did (which may or may not be the "best" way) was redo all the propane lines that were crushed/damaged under the trailer, keeping the usable parts. I disconnected the branch lines, and installed new brass petcocks and double-end female swivle fittings at the existing "T". I routed new copper tubing to each appliance, and poked them up through the floor, using black rubber pipe at the penetration to protect the copper tubing. Inside I routed the copper tube directly to each appliance, and connected with a flared fitting. NO FLEX HOSE!
Underneath I also used a clear, braided hose, with wire ties, split along the length and wrapped along the copper tube, for extra protection. Also use the rubber grommeted clamps, to prevent chafing the tubes.

Here's a couple pics of what I did:

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[jr3149]

THanks to all for the great responses (especially Edglenn)... I now have the information needed to attach the propane and try to hookup the furnace before the snow flys (so i may be able to peck away it it thoughout the winter. I was thinking of using split loom but i like the plastic hose idea better for protection.
Thanks again to all.
JR