Liquid Propane Gas



I am a big proponent of using gas, whether it be natural or liquid propane anytime heating something is required.  But this page was constructed primarily so that I could brag about how good my original, steel LPG cylinders looked after being recertified, fitted with OPD valves, and painted: 



OPD is short for Overfill Protection Device.  Basically, the valve incorporates, among other things, a means of keeping the gas attendant from overfilling a cylinder.  Liquid filled pressure vessels require an airspace to allow for the liquid to expand should the temperature rise.  Most places now will not refill a cylinder if this style valve is not installed.

The picture at left shows the original Rego brand, automatic switchover regulator supplied as original equipment on my Airstream compared to the brand-new, automatic switchover, Fisher regulator used to replace it.  The RV regulator world is a strange place.  The original regulator was, when new, a fine regulating device.  Although it worked well enough to bench test my appliances, it proved too ornery to re-mount on the Overlander, and would have been rebuilt had parts been available.  From a liability standpoint, I guess I can understand why a manufacturer would rather it be replaced.

But replacing it proved to be quite the challenge.  Rego did not appear to want to support the RV world anymore, and the certified propane dealer who refitted & recertified my cylinders told me to go to an RV dealer for a new regulator.  The problem with that is that every RV store I checked only sold a cheap, die-cast regulator which, from what I had read, was not going to stand the test of time.  To me, a regulator should not be a routine maintenance item.

While I am pleased with the Fisher regulator, I was a bit annoyed that I had to pay more than it was worth to mail order  it.  But since safety in gas starts with a good regulator, I bit the bullet & sent off for it.  BTW, I have heard that Fisher now no longer cares to support the small-scale LPG world.  I hope the regulator I’ve got lasts a long time.

Locating the right style gas fittings also proved elusive.  Notice the white flexline in the “before” picture above?  It is a 5/8 ID, plastic-coated, stainless steel line with steel flare fittings which rusted rather badly.  Plans were to replace it, but I have yet to locate an exact replacement.  Swapping fittings at the regulator to accommodate what is offered now is not that big an obstacle, but the ELL gas fitting on the chassis is.  So for now, I had to clean up the old flexline & go with it.

Originally, I planned to retain the original, all metal pigtails which connect the cylinders to the regulator.  But after a misdiagnosis, I decided they were not sealing well, and bought new neoprene hookups.  Although the real problem ended up being a loose fitting, I decided to go ahead and mount the new parts.

In the old days, everyone used copper tubing for gas service as neither natural nor LP gas attacks it.  But there was a period where the odorant added to let one know there was a leak did.  The odorant would react & form some type of scale inside the line which would break off & clog pilot jets.  At one point, the gas industry apparently sold a tin-lined copper pipe to combat this problem.  I say “apparently” because I have never personally seen the stuff in spite of looking for it.  But it appears the industry reformulated the odorant because I have yet to hear of anyone have problems with copper line used for gas service.

If you plan to work on your copper gas lines, be aware that code specifies flare fittings for any gas connection.  Compression fittings are a no-no.  But, although making flare fittings is a bit labor intensive, acquiring the skill is within the realm of most people.  And, the flaring tool is not that expensive.  Make sure, though, to put the flare nut on the line before you flare it.  Keep in mind that a properly flared fitting requires no additional sealant  such as Teflon tape or pipe dope.  If the joint leaks, and the male fitting is not scored, simply cut the flare off & try again. 

I’m told that Code now requires double-flare fittings at all joints.  I have my own thoughts on the necessity of this particular requirement.  But the Code is there to protect the general public

Update 02/21/06:

Turning the Airstream’s gas bottles off the other morning after a night of Number 1 son & me camping in the back yard, I noticed one bottle had emptied during the night.  Although the weather had been around 35 degrees, it struck me strange that a total of maybe three nights in similar weather had emptied a 30 pound cylinder.  But, whatever; Perhaps I had just forgotten a couple of “trips”. 


Up until now, a local Ace Hardware had been refilling my cylinders for around $21, a price I thought was reasonable.  Unfortunately, they now have a “going out of business” sign adorning the place, and a phone call confirmed that they were out of gas.  The odd thing is that they said they had just run out, and to check back later in the week.  Why would they refill their monster tank at this point?


Letting my fingers do the walking, I found a U-Haul place, open on Sundays, who could refill my tank.  Number 1 son & I headed their way.


Now, there are two ways of determining when a propane tank is full.  Both methods require the tank’s hand-valve be open after the refill hose is screwed in.  The first method, and the one I have seen used most often, involves opening a vent screw located on the hand-valve’s body before the liquid propane pump is switched on.  When a steady fog of gaseous propane starts coming out, refill is complete, and valves can be closed, and the pump turned off.  Ace Hardware used this method, and it was easy to see that I was leaving with a full bottle. 


The other method, which I was familiar with, but had never seen in actual use until now, involves venting all pressure in the tank, and then turning the pump on to push liquid propane into the cylinder until a pressure switch shut off the pump’s motor.  The problem is that the cut-off point can be subjective.  But, U-Haul, unlike Ace, metered the amount of propane the bottle took, and although 6.8 gallons is not ‘full’ for a 7.0 gallon tank, that’s all I paid for.  Of note, I only paid around $19 for the refill.


Now for the kicker:  With U-Haul’s method, everything was quiet immediately after the bottle was filled, and before the hand-valve was closed.  When the technician closed the valve, a distinct ‘hiss’ was heard at the bottle’s valve.  Mystery solved!  In the back of my mind, I had always been surprised at how much propane the Airstream went though in general.  I now believe the new OPD valve installed in May ’04 has probably always leaked through the stem when open.


The problem now is that I have to wait until that tank runs out again before a new valve can be installed.  Time to go camping!