Propane pigtails leaking

[Cooter_76]

We keep our TT at my parents' house near the TX coast and use it as a guest house when we visit. The trailer is about 5 years old. Back in April, we went to visit and the propane system started leaking at the tank connections. Seemed to be coming out of the green threaded fittings that screw onto the tanks. I found some new pigtails at a local propane dealer, installed them and everything seemed to be fine. We went back this past weekend and both leaked immediately.
Is it common for these pigtails to fail, or am I missing some maintenance aspect of the system?

[Edd505]

NRALIFR wrote:
The excess flow check valve that’s part of the Acme nut is supposed to shut off the flow of LP if the flow ever exceeds more than your rig would use if all of your LP appliances were turned on at once. The assumption being that if it ever flows more than that, there’s a leak somewhere.

That’s why they make different colors of the nut, it should be matched to the LP system it’s protecting. Apparently your rig came with green nuts, so I assume your systems max usage rate is under 200K btu.

Black is for up to 70K btu
Green is for up to 200K btu
Red is for up to 400K btu

I have a big torch that connects to a 20 lb. LP cylinder that I use to start fires with. It uses unregulated vapor straight from the cylinder, and looks like a flamethrower when it’s going. It’s also very loud. It’s the only propane item I have that has a red nut on the hose.

With red Acme nuts on your pigtails, it will take a much bigger leak to trip the excess flow check valve. :):)

Thanks, good simple explanation, you learn something everyday.

[Cooter_76]

Old-Biscuit wrote:
There are 1 versions of the TYPE I ACME Nut

Older Version the 'thermal bushing' is fully visible
THEY Leak


Newer Version the 'thermal bushing' is not as visible
They are much less prone to leaking



ACME Nuts are designed to be 'hand-tightened' to fully seal
They have to be tight enough to open the spring loaded chutoff vlave inside the OPD Service Valve opening
Stub inside ACME Nut pushing the valve open when properly tightened

When attached to OPD there should not be any leakage from the ACME Nut
If is does....try to hand tighten more
But shouldn't be that hard

I thought I had subscribed to this thread when I first posted it, but I guess I didn't. Then I promptly forgot about it. :S
Thanks for these pics (and the other responses.) I didn't realize there were two types. Not sure which type I have, but the leaks seemed to be coming from where the pens are pointing in the pics. When I say leak, it's more like a gush. Like it's not sealing at all. I did try to tighten them more by hand, but there was no change. I didn't have a lot of time to monkey with it, and we didn't need to use the propane at the time. Sounds like my best bet is to take the tanks and pigtails to a propane dealer to let them take a look. In the meantime I'll see if I can find out which style I have now.

[NRALIFR]

The excess flow check valve that’s part of the Acme nut is supposed to shut off the flow of LP if the flow ever exceeds more than your rig would use if all of your LP appliances were turned on at once. The assumption being that if it ever flows more than that, there’s a leak somewhere.

That’s why they make different colors of the nut, it should be matched to the LP system it’s protecting. Apparently your rig came with green nuts, so I assume your systems max usage rate is under 200K btu.

Black is for up to 70K btu
Green is for up to 200K btu
Red is for up to 400K btu

I have a big torch that connects to a 20 lb. LP cylinder that I use to start fires with. It uses unregulated vapor straight from the cylinder, and looks like a flamethrower when it’s going. It’s also very loud. It’s the only propane item I have that has a red nut on the hose.

With red Acme nuts on your pigtails, it will take a much bigger leak to trip the excess flow check valve.

:):)

[Edd505]

NRALIFR wrote:
The red Acme nut is supposed to indicate that it’s equipped with a 400,000 btu excess flow check valve, which is twice what the green nut is equipped with. You shouldn’t be using the red nut on an RV that wasn’t originally equipped with one.

:):)

Details say: This high pressure fitting is rated up to 400,000 BTU's. If it's under the rating whats the issue?

[trailer_newbe]

Pig tails leak a lot more than you might think. They like to leak where the brass fitting transitions to the rubber hose (either end). The worst pig tails are the ones that you can actually turn the hose independent of the brass fitting. I try to find pig tails that are very tight in this area, because it they aren’t they will be leakers down the road.

[DM6156]

this thread reminds me of an interesting story. Last fall, went on a camping trip to local state park. Left campsite to go on a hike, came back to a hissing sound and after investigating, noticed my rubber hose between tank and rig was chewed up and leaking. I believe a squirrel started chewing my hose! I was able to make it to local TSC (only place open on sunday night) and find a replacement right before they closed. after I got home, ordered new one with steel overbraid, the kind that are often used with washing machines.

[NRALIFR]

The red Acme nut is supposed to indicate that it’s equipped with a 400,000 btu excess flow check valve, which is twice what the green nut is equipped with. You shouldn’t be using the red nut on an RV that wasn’t originally equipped with one.

:):)

[Edd505]

I have been through two sets, both cracked with the heat in the SW. I had a set made by the local propane dealer, he had rolls of hose & boxes of fittings. The new nuts are red not green and he said they were a better fitting.

[Vulcanmars]

Mine leak just as noted by Old Biscuit. Only three years old. I used soap and water in a spray bottle to verify the leak location.

[Turtle_n_Peeps]

Double

[Turtle_n_Peeps]

The pig tails seal on the O ring in the valve of the tank. "If" the pig tails aren't leaking between the rubber hose and brass farel (rare, but it can happen) then you need new valves in your tank(s).

[SoundGuy]

Cooter_76 wrote:
The trailer is about 5 years old. Back in April, we went to visit and the propane system started leaking at the tank connections. Seemed to be coming out of the green threaded fittings that screw onto the tanks. I found some new pigtails at a local propane dealer, installed them and everything seemed to be fine. We went back this past weekend and both leaked immediately.

A dozen years ago we bought a new 2007 RVision TrailCruiser hybrid but a couple years later had the same problem. I replaced both Acme-1 pigtails with new ones but that didn't solve the problem so I bought another set, this time with the older POL reverse thread brass connector instead of the Acme-1 plastic connector. That solved the problem entirely. :B

[Old-Biscuit]

There are 1 versions of the TYPE I ACME Nut

Older Version the 'thermal bushing' is fully visible
THEY Leak


Newer Version the 'thermal bushing' is not as visible
They are much less prone to leaking



ACME Nuts are designed to be 'hand-tightened' to fully seal
They have to be tight enough to open the spring loaded chutoff vlave inside the OPD Service Valve opening
Stub inside ACME Nut pushing the valve open when properly tightened

When attached to OPD there should not be any leakage from the ACME Nut
If is does....try to hand tighten more
But shouldn't be that hard

[BadgerMcAdams]

I know on the ORV forum that they had a Pigtail problem a while back...But, while they can dry-rot over time and prolonged exposure to the sun (just don't make them like they did years ago), I can't see the new one doing the same thing in a very short time. As others said, check the regulator, and for scientific research, make a soapy water solution and put it on the fittings, connections, and any other gas device that you may think is leaking to see what is really going on.

Good luck and hope that you get if worked out!