Very slow propane leak: how to find it?

[profdant139]

Here is the problem: even with all appliances off, but the propane tank turned on, I am losing a quarter of a gallon of propane in a 24 hr. period. (I have weighed the tank -- it lost a pound a day, which is a quarter of a gallon.)

Obviously, I have applied a soapy solution everywhere -- no soap, so to speak. No bubbles.

I bought one of those cheap ($35) propane detection wands -- not a magic wand at all. It did not indicate that it had detected any gas. (I did test it by briefly turning on the stove without lighting it, and the detector lit up like a Christmas tree.)

My wife (who has a great sense of smell) does smell some propane, intermittently, but can't narrow it down, either. She obligingly sniffed every part of the propane system she could reach, without success.

So now what? This is not safe -- I can't ask her to wear nose plugs and then just ignore the leak. There are more expensive propane detection wands -- they cost a couple of hundred dollars. Are there repair facilities with even better equipment?

Thanks in advance for your suggestions.

[time2roll]

Consider capping off the branch lines from the main. One at a time until it is all capped.
I assume with the main tank valve off there is no loss.

[marcsbigfoot20b]

profdant139 wrote:
marcsbigfoot, that sure is a discouraging photo. But it is entirely possible that this is exactly what is happening to me. The only bright side is that DW smells nothing when we are inside, leading me to believe that this is not behind a cabinet or otherwise inaccessible.

But I have got a lot more tracing to do, and I am running out of unexamined places.

Just goes to show, you never know. Gotta check every inch of every line, every connection. At first I thought it was a black tank/sewer issue because it smelled the same....like rotten potatoes.

[Mont_G_J]

Deleted, double post.

[Mont_G_J]

Bottom of propane tank leaking?

[profdant139]

marcsbigfoot, that sure is a discouraging photo. But it is entirely possible that this is exactly what is happening to me. The only bright side is that DW smells nothing when we are inside, leading me to believe that this is not behind a cabinet or otherwise inaccessible.

But I have got a lot more tracing to do, and I am running out of unexamined places.

[marcsbigfoot20b]

MrWizard wrote:

Charles2222 wrote:
Flame and LP gas.Oh boy that’s smart.yea,just an ole master Plumber here

Put it in context

A leak that small in the open outside? Where it does not collect to an explosive amount

A torch flame hitting that leak will flare and show you where the leak is

Same context reverse method as spraying wd40 around a carburetor and intake looking for vacuum leaks

Well, a little different but point made.

You hit a propane leak with a torch and there is the unknown of how big the leak, is it mixed with O2, is there anything flammable affected, possible consequences......and there will be a flame when found.

A carburetor or fuel injected intake manifold is sucking, and isolated by camshaft opening and closing the combustion chamber. So you will see rpm change but no open flame in your face. Now try the carb thing with oxy acetylene mix and there might be a bang when you find a leak.

[MrWizard]

Charles2222 wrote:
Flame and LP gas.Oh boy that’s smart.yea,just an ole master Plumber here

Put it in context

A leak that small in the open outside? Where it does not collect to an explosive amount

A torch flame hitting that leak will flare and show you where the leak is

Same context reverse method as spraying wd40 around a carburetor and intake looking for vacuum leaks

[MrWizard]

I have a pump bottle of red spray leak detector from camco

[marcsbigfoot20b]

I had a small tiny leak years ago that took me weeks to find. I had to buy a propane sniffer also. The problem was the leak was in a spot with no access, very small leak and seemingly impossible to be in that spot.

Long story short a screw holding the heater down to a board was poking through and tapping on the copper line for 15 years before it developed a pinhole.
You just have to be methodical.

[profdant139]

Jetstreamer, the propane detector works, and I ran a test on it. But it does not pick up the slow leak, wherever it is. The leak is about a quarter of a gallon a day -- about 32 ounces, or a little more than an ounce an hour from some little pinhole somewhere. The $35 detector I got at the hardware store is not reacting to that low level leak.

JimK, that is a good suggestion -- turn off the tank and see how long the system stays pressurized. When the gas level drops in the line, the red flag will pop up. I am not sure what that will tell me about the location of the leak, but it is one more data point.

And yesterday, I installed a new regulator. Filled the tank with propane. Weighed it. Weighed it again this morning. Bad news -- the weight of the tank dropped around six tenths of a pound. I will do it again tomorrow, just to verify.

[Charles2222]

Flame and LP gas.Oh boy that’s smart.yea,just an ole master Plumber here

[JimK-NY]

This thread seems to be going nowhere but downhill. I have some suggestions regarding the original problem with a substantial leak that has not been detected with soap or an inexpensive propane detector.

I would start with the most likely sources for a leak. Begin with the tank. I have even had a new tank that leaked. I would turn on the propane, then turn it off. If your regulator has the typical red/green markings, checking for a system leak should be easy. Pressure should be maintained for at least several hours. If the pressure remains, then the issue is the tank. If not the next area I would check is the pigtails. I have had to replace mine every few years. Hoses start to dry out and crack. Next check the regulator, then every visible propane line and fitting on the exterior of the RV. Next look at the water heater and furnace.

[BillyBob_Jim]

dougrainer wrote:

BillyBob Jim wrote:

dougrainer wrote:

BillyBob Jim wrote:

Harvey51 wrote:
When I couldn’t detect a leak with soapy water spray on our old popup tent trailer I tried the very sensitive flame test using a propane torch. It clearly showed the regulator leaking.

LOL.....the old school method. Hopefully your post does not start the safety, plumbing code, and legality ramifications debate about checking a gas line with an open flame.

Old School method?????? I have over 40 years and am Licensed to service LP systems for that 40 years. In the past 40 years there has NEVER been a Flame test. Flame test is one way to win a Darwin award. You will get the medal in the Burn Ward. I am constantly amazed at the DUMB hazardly postings on these forums. Doug

BAZINGA!!!!!!!

And there it is LOL, further proof of a theory of mine that this forum is seriously lacking in the SENSE of humor department. Lighten up Doug, you're evidently a legend in your own mind.

No, Just a LOT smarter than you. Doug

PS, SOME people are just plain stupid and posts like mine help keep them safe. You would rather just watch and then brag about how you were there but did nothing but laugh.

Don't forget your meds today, as evidently happened yesterday.

Now that you have called me stupid twice I sure wish I would have forgone the 8 years of secondary education and went turning wrenches at an RV dealership, so you do have me in that LOT smarter regard I suppose. I would of liked to have done that for 40 years as opposed to where I ended up, being retired at 52.

[Jetstreamer]

I can’t believe that the flammable gas detector wand couldn’t find the problem for you... was it properly calibrated before use? I bought a relatively inexpensive one to trace some leaks and I couldn’t believe how sensitive it was. It sniffed out a couple of incredibly small leaks right away. Ones where I would have never smelled any gas.