Propane tanks or etal

desertrat · 06-29-2011, 04:18 PM

Just spent the last 3 days going through the propane tanks, regulators, and now the "pig tails". After all this is finished and IT IS WORKING ( if ever) guaranty the dealer is going to get a call. Should have made them show us that the gas lines were really working after more than 5 minutes.

So much fun. So much for something new that is SUPPOSED to work.

pschnetts · 07-05-2011, 07:41 AM

I might of had the same issue. My tanks would work when freshly filled for about 5 minutes then nothing. I disassembled everything and started replacing stuff, untill I found the check valves in the pigtails, on the tank end, were too strong and not letting gas pass through. Since there are additional check valves on my auto switch, I drilled out the check valves in the pigtails, and everything seems to work great.

MtnGuy · 07-05-2011, 07:49 AM

Quote:

Originally Posted by pschnetts

I might of had the same issue. My tanks would work when freshly filled for about 5 minutes then nothing. I disassembled everything and started replacing stuff, untill I found the check valves in the pigtails, on the tank end, were too strong and not letting gas pass through. Since there are additional check valves on my auto switch, I drilled out the check valves in the pigtails, and everything seems to work great.

Those pigtail check valves serve a purpose. If there is a free-flow of gas because of a broken line or something, the check valve will shut the supply off. Better to replace the pigtails and throw away the drilled out units. Just speculating, but going down the road with non-working check valves and the gas on may be illegal.

**KyDan** · 07-05-2011, 08:04 AM

New LP tanks have built in free flow preventers.
In other words if the tank sees too much flow it shuts off.
Not sure why pig tails have them too.

**Herk7769** · 07-05-2011, 08:08 AM

Pig tails have one way check valves (not shut offs). They tend to stick from oil and general crap in the gas.
Once they start sticking; replace them.

MtnGuy · 07-05-2011, 10:13 AM

I hate to differ with you guys, but sometimes I just gotta.

Acccording to this article (Propane Safety and Use) (about 1/2 way down starting beside the pigtail photo), the tanks have a overfill protection device (OPD), but doesn't state anything about a limiting device. I have read on this forum that turning the valve on too quickly with a full tank will sometimes make this valve shut.

The pigtails have 2 safety devices. Besides the "flow limiting device", there is a thermal-sensitive bushing that will melt under extreme heat, closing a piston at the cylinder valve, shutting off gas. That is the 1st time I have read about that safety feature.

The paragraph under that explains how the "flow limiting device" works. I had no idea it was so complicated, but that may have been what was happening in Post #2.

**Herk7769** · 07-05-2011, 11:23 AM

Chap,

I think we are talking about the same thing. I was talking about the pigtail and not the OPD which is INSIDE the tank and valve body.

The pigtail goes from the threaded part of the valve to the regulator. Acme Nut (or POL fitting) to the hose to a NPT fitting. It is the Acme Nut I was referring to.

There is a spring loaded valve in the Acme Nut that allows propane flow from the bottle to the regulator but not from the regulator back to the bottle. That way you can change out the bottles without a gas leak. They stick when dirty, especially when cold. Drilling them out is a really bad idea for the reason you stated. In a fire, they melt SHUT and prevent a huge propane torch. The down side of course is if the fire lasts a long time that tank is a bomb.

Propane 101-The basics

Was my reference, but having read your article it makes more sense regarding the flow limiter.

**Herk7769** · 07-05-2011, 11:35 AM

I spent a lot more time re-reading both articles and Chap is the most correct. In any case, replace that pigtail.

pschnetts · 07-05-2011, 11:43 AM

I didn't expect this many replies, but thanks for the help. Our camper has done this since new and the dealer said nothing is wrong. I drilled the check valves in fustration as a hungry family was waiting inpatiently. Do you still think I need to replace them when 12" further down the line there is another check valve on the switching valve/regulator?

**Herk7769** · 07-05-2011, 11:49 AM

I believe Chap will back me up when I say "Yes, you should." They are not all that expensive and it would be a DoT violation if you were ever stopped.

Additionally, you have bypassed a required safety item on your camper. it would be the same as replacing all your GFCI electrical outlets with standard ones or taking the batteries out of your smoke detectors.

MtnGuy · 07-05-2011, 12:35 PM

Definitively replace those drilled out pigtails.

Reading the article that Lou posted, combined with the 1 that I posted, gives me a better insight on how the whole system works. Until reading Lou's link, I did not know that we need to insert a pigtail on the cylinder to open up the OPD so there can be flow out of the cylinder. Knowing that now, maybe 1 of the 1st things we can advise members that can't get their propane flowing is to make sure the pigtail is screwed on hand tight.

According to paragraph 4 in Lou's link, I incorrectly used the word "tank" instead of "cylinder". We have removeable "cylinders" on our TTs and 5th wheels, but there are non-removeable "tanks" on motor homes.

jimh · 08-25-2011, 02:15 PM

i liked the propane 101. the only safety that i knew abt was the over fill protection.
we had blow out protection on sight glasses at work; wondered why they weren't used on travel trailers. apparently they are built into the system.

Timex · 08-25-2011, 03:19 PM

Guys, please be careful with those pig's tails. If they move from one side to the other, gas will pass!

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