Leak at propane cylinder

[bobinyelm]

I recently purchased an Olympian Wave 6 heater for my RV, but until I tap into the propane system, I bought a flex hose with a small regulator that attaches directly to a propane cylinder via a rigid POL fitting that threads into the internal left-hand thread of the OPD type cylinder valve. "It's a Red Dragon SL-1C Propane Hookup Kit"

Unfortunately, no matter how tightly I snug the fitting into the valve*, the connection leaks very slightly. It can be heard, smelled, and verified with soap bubbles.

Click to see fitting described: 2012-02-17_0011 - bobinyelm's library

The O-Ring on the fitting is fine, and the one inside the cylinder valve looks fine as well.

The fitting is not leaking enough that the Wave Heater doesn't work, but it IS enough a close ear can hear the "hiss."

What is usually the reason for such a leak? The fitting (even though it LOOKS fine), or the interior of the valve?

Bob

[EngineerMike]

bad o-ring despite the look, bad machining on the female or male fitting part. Whatever, I'd replace the o-rings first & see it that seals it, then female part, then OPD valve till I fixed the leak. Leaking propane no bueno.

[Dunner]

I had the same problem with one of the 30# tanks on my 5er. There was no way I could replace the O-ring in the tank valve. Some are replaceable, some are not. I found a replacement tank fitting at an RV store. You screw it in the original valve until the install nut breaks off. Worked fine after that. I think the original O-ring got damaged because it was dry when the tank was refilled at a local gas station.

I did a quick search and couldn't find it.

[Full.Monte]

The key is WHERE is it leaking? Where do you see the soap bubbles? I have one that leaked at the pipe thread fittings between the nipple and the o-ring adapter. I disassembled it carefully and used pipe dope to re-seal it. It works now. It leaked as it came when brand new.