Strange Propane Pigtail Failure

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Foto-n-T

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A month or so ago I filled one of my 30 pounders and re-installed it in the propane bay.  When I screwed in the pigtail that leads to the regulator and opened the valve on the tank I had a significant leak (I know, any leak is significant).  Since it was dark and I was tired I gave up after a few tries and just left it disconnected.  The next day I went out in the daylight and it hooked up no problem.  I chocked this up to my own fatigue and inability to master the simple task of screwing on a coupler correctly.

Two days ago I again filled and changed tanks.  This time in broad daylight when I went to connect that same pigtail I had the problem re-appear.  Since I'm in one spot for the winter I don't tie the tanks down and the regulator was hanging down a little farther than it should so I lifted the regulator up.  When I did this I got an immediate leak from the pigtail coupler.  I'm assuming that there is an O-ring in the coupler ring itself that seals the hose, it appears that the O-ring may have failed and will only seal when the hose is a perfect 90 degrees running through it.  I'll be on the hunt today at Sutherlands or worst case an RV store to replace both of them but I'm curious if anybody has had this particular failure occur to them.  Normally I replace these things when they get hard and brittle but these ones are only about two years old and are in very good shape other than one of them can't hold propane anymore.

I would suggest that when anyone re-installs their propane tanks that they "jiggle" the hoses once the propane is turned back on to verify that they don't have a failure of this sort.  Since the working pressure of a full propane tank is 250 psi, any leak should become readily apparent.  If I hadn't moved that regulator and jiggled the pigtail this could have lead to a VERY serious problem.
 

Alfa38User

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I don't purposely jiggle them but I have never detected any leak on the high pressure side. I did change those pigtails about 5 years ago as the old ones seemed too hard and perhaps brittle. The "new" ones are now quite hard again and somewhat difficult to move easily.

I got very annoyed with that tie down bracket and regulator falling down on the threaded rod when the tank(s) had to be filled so I got hold of another nut and large washer for the rod and threaded it down so the bracket could only fall down a limited amount but still move enough to unhook. Works so far!! Like you, I don't keep them fastened down while in one spot for a while (which, in our snowbird home, is always), but I do secure them when we close up for the summer and don't loosen them again until the first time I need to remove a tank.
 

Foto-n-T

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Cody, Wyoming - Sometimes
I went into town (10 miles) to hit the grocery store and check out the local RV supplier.  They have the pigtails but they like 'em a little more than I do.  Since I've got a full bottle operational and I'm not in a big hurry I'll just order them on Amazon and they'll show up in a few days.

By the way, free shipping when you bust the $25 mark on these items and since together I made that goal I'll just do it that way.
http://www.amazon.com/gp/product/B0014E3MSS/ref=ox_sc_act_title_1?ie=UTF8&smid=ATVPDKIKX0DER

I'm still a little confused as to "why" I had this type of failure.
 

Alfa38User

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Just a heads up on new pigtails: When I got the new pigtails home from the propane dealer, I found out the thread sizes did not match up. Went back to the dealer with the intention of  returning them and he simply handed me two brass adapters to solve the problem. The pigtails may have had metric fittings and the trailer may have had US sized ones.
 

Kamper Dave

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Feb 3, 2011
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195
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Wisconsin
After reading this article, I wonder if the temperature shut off inside of the pigtail broke or failed.
http://www.rvdoctor.com/2001/04/not-your-fathers-pigtail.html
 

Foto-n-T

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Location
Cody, Wyoming - Sometimes
Very interesting article Dave, I had no idea there were sooo many moving parts inside of those little green knobs!!

After reading the article I think you've found the answer to my problem.  It appears that the ring that the author was talking about had somehow only partially failed allowing gas to escape but not triggering the piston to close off the flow.  I had since the introduction of the OPD valves over a decade ago believed that the OPD itself was responsible for shutting down the gas flow in the advent of a large leak, turns out it's built into those green knobs not the OPD on the tank.

I ordered two new pigtails from Amazon and the ones that I received have the O-ring on the exterior.  I haven't installed either one yet 'cause I've been working too many hours but today I'll get the failed one at least replaced.  I'll probably leave the other one alone for now and just hang onto the extra as a spare.  Thanks again for the link and I encourage those subscribed to this thread to read it.
 

Kamper Dave

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Feb 3, 2011
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195
Location
Wisconsin
I am glad to hear that the article was helpful.
I have heard that many good regulators have been changed out because of this safety device.
I may be shooting myself in the foot, but I installed a gas shut off on the main propane pipe located under the propane cylinders. When changing cylinders or hooking up the big 100 gallon unit I turn off the propane until I am done with the changeover.
Kamper Dave
 

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