Is smelling some propane at the tanks normal?

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Lonestar Guy

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I have a one year old travel trailer. It seems like every time I open the propane tank cover, I detect some gas smell, even when the valves are OFF. I applied kiddie bubble solution at all the joints and connections with valves closed and open and I see no bubbles. (This assumes the kiddie bubble solution is acceptable for leak testing.) So, I'm just wondering if, although it might be an infinitesimal amount, is it acceptable to smell some gas at a given time, perhaps more so upon stopping after traveling? Otherwise, do I need to find a more surefire method for leak checking? Thanks!
 

richclover

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Lonestar Guy said:
I have a one year old travel trailer. It seems like every time I open the propane tank cover, I detect some gas smell, even when the valves are OFF. I applied kiddie bubble solution at all the joints and connections with valves closed and open and I see no bubbles. (This assumes the kiddie bubble solution is acceptable for leak testing.) So, I'm just wondering if, although it might be an infinitesimal amount, is it acceptable to smell some gas at a given time, perhaps more so upon stopping after traveling? Otherwise, do I need to find a more surefire method for leak checking? Thanks!

JMHO, Gary, but, no, not normal.  You might find a shop that deals in propane tanks and equipment.  There are very precise meters that can be used to localize your problem.
 

Henry J Fate

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Shouldn't be any gas leaking at the tank. If you are able to smell gas each time you check it, most likely you have a leak. You can go out to any hardware store and buy a bottle of bubble test. Use that to swab areas of the tank and the lines.

A known device to leak is the tank shut off valve. Those valves work best either all the way closed or all the open. With the valve open, soak the stem of the valve with the bubble test.
 

Rene T

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Do you have a regulator right there?  If you do, soap test the bottom of it. There's a small drain hole on the bottom side.
 

Lou Schneider

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Along with everything else, propane itself is odorless.  What gives propane it's smell is mercaptan oil added during processing so you can smell a leak.

Since the mercaptin isn't a gas, if it gets out of the tank it can land on a surface and continue to smell for a while even if there isn't any more propane leaking out.

With the onset of hot weather, you may have had a slight burp out of the overpressure valve as the propane expanded when the tank heated up, releasing some mercaptan you're continuing to smell.  Especially if the smell is coming from the cover instead of the tanks or hoses.
 

Isaac-1

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As mentioned above spilled Mercaptan oil, perhaps out of an over-pressure relief can smell for a very long time , a tanker truck carrying Mercaptan spilled on a rural highway near a town about 30 miles from where I live some years ago, for nearly a decade I could smell it whenever I would drive by the location of the spill.
 

John From Detroit

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Sometimes if a tank is filled to the cut off point (80%) when cold (Say 60's) and then it's 100 in the shade and the tank is in the sun the liquid will expand faster than the steel and it will vent slightly.

BUT I've only seen it one time in over a decade of living in an RV full time and 50 years of living with propane.
 

Gary RV_Wizard

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It's not normal, but not exactly a pending disaster either if the amount is faint. The area is outside and ventilated, so the risk of a gas fire is tiny.  I'd still find and fix it, though.


It's worthwhile to wash down the tank and regulator area to get rid of any residual smells. Dish detergent and water works. I'm not saying that's the cause of your aroma, but it's a possibility and easy to eliminate. 


I've not ever seen the Kidde brand of bubble solution, but if it says it's for gas leak detection, I'd have no reason to be skeptical. It's not a magic solution - plain old soap & water works just as well.  The problem with any bubble-type method is that you have to hit the right spot at the right time. Very slow/tiny leaks are easy to miss.

You can get a relatively inexpensive "sniffer" for around $30 (the pro grade models are $200 or more). The cheap ones work adequately for most purposes.
https://www.amazon.com/slp/gas-sniffer/m3jzvhc7w7wd3z7
 

Alfa38User

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I've not ever seen the Kidde brand of bubble solution...  snipped...
I think the OP meant the solutions sold in various stores for kids (children) to make bubbles using a wand. But, as you said, regular soap and water will work fine too.
 

Lonestar Guy

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Sorry about the confusion on the bubble solution. Yes, I just meant childern's bubble solution (well, I guess some adults might blow bubbles too... or grandparents... :). Thanks for all the suggestions. I will clean the whole area first. Yea, I'm in TX so it's warmed up quite a bit now. I will wash the area off and make my own bubble solution. To be clear, it smelled after driving when the valves were OFF and one of the tanks was nearly empty. Since the regulator is after the valve, it doesn't seem like it would be the regulator. Although, it could be the valve was not tight (tight) so who knows. I'll get back to you.
 

viceprice

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We had to replace one of the short flexible hoses that connects to the tank after just 2 years of ownership. (purchased new 3/16). I was amazed at the deterioration of the rubber. It leaked enough that I could smell it but not fast enough to cause the safety valve in the tank to shut it down. Strange that only one of the two hoses was bad. Of course I am keeping a close eye on the other.
 

Lonestar Guy

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Well, I cleaned the tanks well with car washing soap. It seems it doesn't smell as much but still some smell, especially and mainly if cover has been closed (which makes sense). It's mid 90's now where I live. If it's heat related as some suggest, that's probably it. Otherwise, I may not have thoroughly cleaned off all the mercaptan oil IF that is the cause. I will continue to monitor and check for leaks and see if it goes away when the weather cools off in a 2-3 months.  Thanks for everyone's input.
 

Gary RV_Wizard

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A leaky diaphragm in the pressure regulator can bleed a bit of gas out.  Yours is only a year old and should be good for a long, long time yet, but stuff happens...
 

Lonestar Guy

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Thanks, but would that not only be an issue when the gas valves are turned ON? What I'm smelling, is with the valves OFF.
 

Rene T

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Lonestar Guy said:
Thanks, but would that not only be an issue when the gas valves are turned ON? What I'm smelling, is with the valves OFF.

Do a soap test around the valve stem to see if the stem is leaking and that's where smell is coming from.
 

Lonestar Guy

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Rene T said:
Do a soap test around the valve stem to see if the stem is leaking and that's where smell is coming from.

I did that previously and didn't see any bubbles. I may try again.
 
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