New Propane Systems Installation Question

[theidner]

Hello Everyone I have a couple quick questions about installing a new propane system for a two burner propane cooktop and catalytic heater.

Here's a quick backstory so you have the complete picture: We recently purchased a renovated 1976 13' Scamp. The previous owner did a pretty nice job with a lot of his restoration work, but his intended use is obviously different than mine. He removed all the 12v and propane systems completely. I think he was intending to use it plugged in exclusively. We intend to do the exact opposite. So our first step in making that possible is reinstalling a propane system.

I already have the propane tank mounted on the tongue. I have purchased a Dometic two burner cooktop (which I've already physically installed) and a Camco Olympian 3 catalytic furnace. Here's where my question begins...

The furnace requires a low pressure regulator (11" w.c.) which I have already purchased and tested with the furnace and a short bit of hose and it works fine. The cooktop manual doesn't mention a pressure regulator ANYWHERE in the manual and it looks to me like there's already a regulator on the unit right where the propane line comes in.

Just for grins I tested the cooktop hooked up to the propane tank through the same regulator that I bought for the furnace. It seems to work just fine that way, even if it does have its own built-in regulator.

So my question is this... where is the best place to split the propane line? Meaning, can I hook the low pressure regulator directly up to the tank and then split the line afterwards and run to each appliance, or should each separate line have its OWN regulator? Or does the cooktop even need one at all (presuming that it does have one built-in)? Or would it hurt to run it behind another regulator?

I'm pretty good with electrical, but this is my first foray into installing (instead of simply using) propane.

Any helpful ideas? From what I've read here so far, there are ALWAYS helpful ideas.

Thanks in advance!

Troy

[gordon2]

Typically it's single two-stage regulator for the entire camper (11 inches WC). My Suburban stove does have a regulator inside but its still supposed to have a 11 inch WC supply just like everything else in my camper (fridge, Wave II, furnace). The reason is the actually burners operate at something less than 11 inch WC but the stove should have a 11 inch WC supply. Also the total BTU load is part of the planning.

As for routing of lines.. I have no expertise in that area. I have heard it is preferable to run a main line under the camper with branches to the various appliances, keeping most of the piping outside. Of course Scamp does not do that. (Scamp also has improperly mounted the regulator on single tank set ups for years.. just follow the directions for the regulator). Propane uses different copper line than plumbing and don't let it flex in a moving trailer.

The important thing is that all fittings need to be accessible and easy to bubble test or even replace if needed.

And of course proper use of threaded and flared connections. Thats a whole other subject.

[John in Michigan]

Agree with everything Gordon said. Generally:

- one two stage regulator (11" w.c.) mounted on the front close to the tank or directly on the tank
- flexible rubber tube from there to the bottom front edge
- copper tube encased in rubber hose OR steel pipe running under the trailer
- separate branch from under the trailer to each appliance (copper or rubber tubing) protected by a grommet in the subfloor
- all joints have to be accessible for periodic leak testing
- EDIT: the copper or rubber tubing, pipe, all fittings, etc must be suitable and certified for use with propane

This is a project for a certified tech or plumber.

[gordon2]

Agree with everything John said. Generally:

Good expansion of my brief comments. Thats the point.. there is more to know so best to have a professional involved.

If you insist on DIY then I assume you have a manometer and know how to use it, and know what tests and measurements need to be done. One example, measuring the pressure with a BTU load present that is calculated for the system.

[Casita Greg]

Deleted, (duplicate post.)

[Casita Greg]

One key point on physically running, and particularly "splitting," propane lines is that any branch line connections to any appliances must be made outside of the passenger compartment by code, (RVIA and NFPA 1192 Standards for Recreational Vehicles.) Most manufacturers use compression "T" fittings or "4-Way" cross compression gas fittings which they mount under the trailer or RV.
The codes require that no appliance gas lines can be "Tee'd," branched or piggy-backed from, on the individual dedicated gas pipe inside the trailer. The only gas line fitting allowed inside is the ONE fitting that the appliance actually hooks up to. No other connections of gas lines are allowed to be made inside the trailer.

A suggestion would be to run your main supply line along the inside of the frame rail, add a distribution block to accommodate however many appliances you have that run on propane, and stub the piping up from underneath the trailer to feed each appliance.

I would also recommend getting yourself a small inexpensive tubing bender to avoid kinking or collapsing the tubing while bending it to form your radiused turns. Most RV appliances also come with a gas inlet fitting requiring a flared end compression fitting, so you may want to "beg, borrow, or steal," a hand operated tubing flaring tool as well. (Don't forget to drop the female compression fitting onto the pipe before you flare it too.)

[gordon2]

Originally Posted by Casita Greg

One key point on physically running, and particularly "splitting," propane lines is that any branch line connections to any appliances must be made outside of the passenger compartment by code, (RVIA and NFPA 1192 Standards for Recreational Vehicles.)...

And Scamp (Evelands) has not been doing it that way for decades. Lots of tees inside perhaps tens of thousands of Scamp trailers.

Not saying this is the way to do it.. quite the opposite actually.. but its a fact.

[wilyoung]

I am not familiar with Scamp and their propane plumbing, but I don't see how they could get by with not plumbing to code. If that is true insurance companies must know that. Is it possible that insurance companies will insure a trailer known not to comply with code? Or are Scamps uninsurable? What about state DOTs? Will they let thousands of known non-code vehicles use their roads?


All that aside, if you are doing your own propane plumbing get a copy of the code and stick scrupulously to it. Including grade of tubing, fittings, regulators, and where they are placed.


Wil

[theidner]

I knew this was the place to come! Lots of great information. I actually do have a manometer (more than one) and know how to use it. I am an engineer. But that in no way makes me an expert in LP gas. I'm also fairly cautious and conservative by nature. I will definitely look up the RV code that sounds like a very useful resource. I may even involve some professional assistance. On the other hand... I've been looking for an excuse to buy a tubing bender and flaring tools.


Thanks for the input! I'm sure I'll have more questions before I'm done customizing this trailer for our purposes.


Troy

[Roger Kimble]

Your going in the right direction!