Propane smell with valve closed

[Radar22]

Hello,

I consistently smell propane outside coach with the valve closed. I did a soapy water test to see if there was anything bubbling and couldn’t find anything. Should I do same test with valve open? Any suggestions? Thanks 

[Tom Cherry]

4 minutes ago, Radar22 said:

Hello,

I consistently smell propane outside coach with the valve closed. I did a soapy water test to see if there was anything bubbling and couldn’t find anything. Should I do same test with valve open? Any suggestions? Thanks 

Did you test or soap down, with the valve OPEN…as well, all the joints and the regulator and the exposed plumbing going to the front?

The other question, when was the last time you filled the tank?  This is a C&P from another site….at the end….putting it in the middle messed up the text editor.

The question is….what other source or component would release vapor.  I would totally soap or bubble test all the fittings on the tank. Remove the cover from the fill connection and such.

NOW…two other remote possibilities….the tank was overfilled, and will expand during a temperature rise.  The other is that when the tank was filled, the bulk tank was low and/or, there was too much Meraptan oil added….that is the oil that provides the pungent odor.  You could use a small bucket full of hot water and a few shots of Dawn dishwashing detergent and clean the entire tank (put a plastic bag over the gauge) and then rinse.  If there was a discharge during filling…it will linger…big time.  I once KNEW that my new 120 gallon gas log tank was defective.  I purchased it….had it filled….brought home and installed it.  It smelled….for a few days….then never again.

The other thing would be to drive to a large propane distributor….one who has a fleet of trucks for home or farm or industrial delivery.  They often have to “safety check” a new customer’s tank…. There is a protocol.  Let them check or inspect your tank…

OR…loosen the “vent” slightly…let it blow for a second…the hand tighten….clean or wash the area around it….and wait a few days…then do your sniff test….

The "vent" that they open while filling tanks and cylinders is not actually a "vent" at all. It's official name is the "Fixed liquid level gauge", and it's connected to a calibrated tube that vents gas until the liquid propane reached the tube. The difference is readily apparent when that happens. Refillers that fill DOT cylinders by weight often don't open the gauge valve, and most of the time, the correct weight will be reached just before the OPD valve trips. The fixed ASME tanks on motorhomes can't be filled by weight of course, so the level gauge should always be open while they're filling.

[Radar22]

Hi Tom,

‘Thanks for the reply. The tank valve has not been opened for a few years so I don’t know where it could be leaking from. I did purchase a new regulator and will install but don’t know if that’s the source of the leak. I will open valve and do soapy water test. 

[Donflem]

If memory serves me, a lot of people were having problems with the pressure regulators leaking. I had a problem with mine kept smelling propane, finally figured out it was the pressure regulator no problem since replacing that.

[Tom Cherry]

5 hours ago, Radar22 said:

Hi Tom,

‘Thanks for the reply. The tank valve has not been opened for a few years so I don’t know where it could be leaking from. I did purchase a new regulator and will install but don’t know if that’s the source of the leak. I will open valve and do soapy water test. 

The regulator is on the “outlet” side of the valve.  If the valve is closed, then there is barely 0.5 PSI in the system between the regulator and your appliances.  Don’t know exactly how that could leak.  Now, if you got some super saturated propane with mercaptan, maybe…. If you see an oily residue on the inside of the old regulator…a telltale sign.

There are two regulators that will fit or come up as a “new part”.  They vary in capacity.  If you ever intend to hook up a big fire pit to your MH, get the bigger one….or just get it and drive on.  The smaller capacity will work…

[96 EVO]

A friend had this issue with his Tiffin. We 'thought' we had sprayed every fitting / valve there was, with no bubbles appearing.

He recently informed me he found the leak at a drain? plug right on the bottom of the tank, which we had never seen!

[tmw188]

Replace the hose too. 

[Robert92867]

No help on the propane smell, but I looked at the pic of your rig in your profile.  That's cool how the condensate on the outside highlights all the structural elements hidden behind the walls.

 

[jmatusic]

Not an expert by any means, however, I’ll add my two cents. As mentioned above, the valve has a component that acts kind of like a hot water heater relief valve. If the pressure inside the tank get too high, the valve will vent (even if turned off) until the internal tank pressure gets below the level the relief valve wants. I have been told that’s why the stores that sell replacement tanks, like for barbecues, etc have signs on the door to keep them all outside. The temperature of the tank will affect the gas pressure inside the tank, hotter outside, higher pressure inside, valve may vent, you’ll smell it. I park my coach where the evening sun heats the door to my tank, I’ve never measured it, but I bet the tank gets warm. Good luck.

[Radar22]

Interesting thoughts. I bought a leak tester and will continue to probe. Thanks 

[SUCHESTOM]

We start with a test block installed between the tank valve and the pigtail or piping when testing in the propane business.   Be sure all propane outlets are off, valves off.  Turn the system on and pressurize it, cut the gas off with the test block and see if it holds pressure.  If it does not hold pressure, there is gas leaking in the piping system, regulators, or appliances provided you have no leaks at the test block (Test with soapy water to be sure.)  If it holds you need to wash your tank with soapy water.  I have seen them leak in the welds, and even in the steel before. (RARE)  Typically in the bonnet, gauge gasket, fill valve, or around threads where things are attached to the tank, or openings are plugged.   If you are using an electronic leak detector, be sure it works.  (test on gas).   We have also found open sewer vents and dead animals that were decomposing when called for a leak. You can't afford to get this wrong, you can not safely travel with a leak, consider getting a propane service tech to investigate.