Propane hoses

[Carl in St Augustine]

I have a bad hose on a Montana 5ver. The hose runs from the regulator to the fitting on the pipe running to the opposite side. It is 3/8 inverted flair (female) on one end, with a 1/4 flare male ,to the regulator, on the other end. Have not been able to locate this hose any where! Does any body have a good source for hose assemblies? This would be a high pressure hose right off the left tank to the regulator. Keystone must get them from some where.

[TXiceman]

A lot of the places that sell gas grills and service propane tanks have the ability to make up custom hoses. Might try one of the propane dealers.

With the propane you need to stay with the flare fitting and do not go to the compression type.

Ken

[K-Star]

first, welcome to iRV2. We hope you continue to visit and share your experiences.

try giving this place a try.

http://http://www.folandsales.com/store.asp?pid=16163

I've looked thru this site for other parts, however never ordered from them

[Carl in St Augustine]

I am trying to stay with flare fittings but if I can't, I will go with a pipe thread adapter on the regulator end, with some copper anti seize. Done this before and it holds OK but it's not the way to go if I can help it.

Thanks for the replies...

[Carl in St Augustine]

Well. I am going to rebuild the whole system. Want to get rid of the really poor engineering that they did on the Montana. Isolation check valves, reroute gas lines out of front bay to avoid ignition points and new hoses and flip flop unit. Get rid of the junk iron pipe they used up front and install new hoses routed in protective shields. Thanks for the replies.

[RVDude]

I am sure you are aware that there is certified LPG "rubber" hose (they are not air hose)...

Many full service propane shops and even many RV repair places have the LPG hose, the crimp tool, and fittings - as I recall it's around a $1/ft and a couple bucks per fitting/crimp.

The use of iron pipe in LPG and NatG is an industry standard. Why do you think they are "junk"? Seems it was the rubber hose that failed you?? Just curious.

[Carl in St Augustine]

Yes, the iron pipe is standard but with an iron reducer and nipple, not a brass fitting with tapered thread on either end. A tapered thread on a pipe thread will split the nipple eventually and produce a gas leak in an area with ignition sources, without good ventilation. A fire waiting to happen. It's just much safer to reroute with the proper hardware. Saving a little weight, perhaps, by using the proper hose and getting rid of the iron pipe. What they used to support the pipe was very weak, needed to be fixed any way. I am replacing all with propane rated gear and reducing the pressure routed across the coach, to reduce the chance of leaks also. Talked to engineering at Marshall Gas, who build the components, and they have the design I needed for a better system. Also installing check valves to eliminate flow back in the case of a leak and to prevent condensate in the hoses.

[TXiceman]

"Also installing check valves to eliminate flow back in the case of a leak and to prevent condensate in the hoses."

I don't understand the reasoning here. You are working with very low pressure (inches of water column). The gas will flow from the higher pressure point to the lower pressure point.

Ken

[Carl in St Augustine]

As per the engineers at Marshall, it has a lot more to do with temperature changes and hose routing , than pressure. The idea is to keep any liquid from reaching the regulator and taking out a diaphragm.

Here is a link to the company web site. Go to the "information" tab.

http://www.shleggitt.com/

[RVDude]

The back-flow valve will eliminate the "pssst" when you disconnect the remote tank. Has nothing to do with temp or condensate.

[Carl in St Augustine]

Right. And a back flow valve at each regulator stops any liquid from getting into the regulator.

[RVDude]

Actually, the back flow will only stop liquid (or whatever) from entering the regulator ONLY if the flow is somehow reversed through the regulator and back flow valve. Since that really can not happen - how in the world will the flow reverse in a LPG system - the back flow valve will really do nothing in terms of liquid entering the regulator. Any gas in the line after the regulator that somehow precipitate into a liquid because of a massive, huge, sudden swing in temperature - possible just in no way plausible - that liquid will only be stopped from entering the regulator only if the pressure on the entry side to the back flow valve is less than the exit side. A sudden pressure reduction of the gas will only keep it a gas. But, given the gas that just allegedly condensed into a liquid, that state change brought with it a huge reduction in pressure on that side of the valve so even the pressure equation won't push liquid back into the regulator - the pressure is less on the exit side of the valve.

Again, the back flow is just for user convenience to arrest the "psst" when a line is detached as liquid control (if there is any) realistically can not, does not, and will not enter the equation.

It's just a fun project adding in more mechanical break points and increasing complexity that has no meaningful safety addition or system protections. But, heck, it's fun, go for it!

[Carl in St Augustine]

You are correct sir, I had it backwards. The main reason I am doing this is to lower the pressure in the line coming across the coach from the remote bottle. Lower pressure seems like a good thing and I get rid of the bad connections at the ends of the iron pipe and get the check valves as a bonus. I was all ready having problems with the iron pipe connections then a hose went, make that two hoses, so it was a good time for a rework.

[Carl in St Augustine]

Update: Relocated original pipe to under the frame in back of hose storage, installed a reducer at each end to accomidate a flare fitting. I installed a 30lb. regulator in the remote bottle compartment so only 30psi is going through pipe to main side. Replaced the old flip-flop with a new one and replaced all hoses. Works quite well now but I must have a very slow leak on the main side. I get a whiff of gas every so often. Back to it with some leak detector and wrenches and should be good to go.

When I pulled the old fittings off the iron gas pipe one was cracked, a hairline that was all but invisible when installed, and I had two bad hoses.