Intermittent Propane Odor

[BugsyJ]

My wife and I get propane odors from time to time in our 2016 27FB. When we were in Jackson Center early this summer we had them run a pressure check on the system and they assured us that there were no leaks. We have also never had the propane sensor alarm activate.

The smell is always centered around the stove/fridge/water heater area and seems highly unlikely to be bleeding off from the tanks themselves (windows closed; and it's typically a weak odor in the bedroom closest to the tanks). And, it doesn't smell like sulphur - I have seen others attribute odors to the batteries on this forum.

We are almost always running the fridge and the water heater on electric. I've tried keeping the pilot light in the oven lit (we normally keep it off), but this doesn't seem to have made a difference. And, if we stick our noses in the oven, it doesn't seem particularly strong there.

Although it does happen sometimes randomly, we most consistently smell it when one of the tanks is near empty (but before the regulator has indicated that it has switched tanks). I have seen others on the forums note this as well, but have not read an explanation; it seems counter-intuitive to me as this is when the pressure from the bottle should be at its lowest.

Anyway, thoughts on what this could be and how to fix it would be appreciated.

[Al Boondy]

Since propane gas has no smell, for safety reasons they add an odorant called ethyl mercaptan. The odorant can concentrate on the bottom of the tank and when propane level is low the gas can have too much ethyl mercaptan in it for a small pilot light to burn off. Hence the smell when tank is low.

[nvestysly]

Originally Posted by Al Boondy

Since propane gas has no smell, for safety reasons they had an odorant called ethyl mercaptan. The odorant can concentrate on the bottom of the tank and when propane level is low the gas can have too much ethyl mercaptan in it for a small pilot light to burn off. Hence the smell when tank is low.

We experience a similar problem with our trailer. Usually when one of the tanks is low. Your explanation makes sense. I'll do some more research and double-check if there is a way to drain the tanks of the "extra" odorant. Perhaps emptying the tank on the trailer, then allow any remaining vapor to escape, remove the valve and actually drain the tank. Maybe even rinse the tank. Sounds like a professional "propane guy" needs to do this if it's even feasible.

I can imagine an accumulation of the odorant in tanks on our 1992 but it seems an odd situation to have this accumulation on a relatively new set of tanks. Perhaps I still don't understand the scenario you described. I've seen a thick, oily substance in the bottom of tanks that have been opened and that substance certainly contains a high concentration of odorant. Does it accumulate over time?

[BugsyJ]

Originally Posted by Al Boondy

Since propane gas has no smell, for safety reasons they add an odorant called ethyl mercaptan. The odorant can concentrate on the bottom of the tank and when propane level is low the gas can have too much ethyl mercaptan in it for a small pilot light to burn off. Hence the smell when tank is low.

Thanks for this. But what pilot light would be burning it off? We almost never have ours on in the oven. There is no other one, is there? Or is it just that there is excess that won't burn when we are using any propane? I'm almost certain this has happened when we haven't been using any propane (no stove/oven, fridge, water heater or furnace), but I guess I could be mistaken.

[Bigventure]

Use some soap solution on the gas pipes fittings.