Originally Posted by steve dunham
I have taken 3 new "Prepurged" 20 lb propane cylinders into be filled . Every propane dealer I visited in my area required the tanks to be purged or they would not fill the tanks.
The propane dealers had zero faith in the reliability of prepurging.
Interesting. I have no faith in most of the places which sell propane, because they are clearly not competent:
- almost none check the condition of the cylinder or the certification date (Costco is the only exception I've seen)
- small cylinders are filled by weight here, and none (except possibly Costco) ever check the tare weight
- one young guy and the female "trainee" at a major truck/RV stop chain were so busy flirting with each other that they walked away from my motorhome leaving the bleed valve wide open to endlessly discharge propane vapour
- the propane dealer which sold me a used and recertified (by them) large cylinder did change the valves (at least they looked new), but didn't stamp a new certification date on the collar
- the same propane dealer that sold me the cylinder without the stamp has since repeatedly filled this cylinder, never noticing that it does not have a valid date
- one idiot even filled a 30-pound cylinder with no scale and not using the bleed valve, counting on the Overfill Prevention Device to stop the fill
I suppose I could go to a propane specialist - rather than a gas station - for the first fill, but the place that didn't stamp my cylinder is one of these. Given the places most of us buy propane and my experience with them I would rather trust the factory that make the cylinder than the kid who may have taken the propane course.
Realistically, once the cylinder is vacuum-purged at the factory, even leaving the tank valve wide open won't introduce more than 6 grams of air and less than a gram of water into the cylinder (unless you pump air or water into it, or put it underwater). The concern explained in the article is that a cylinder which has ever been purged may be pressurized with contaminated air, but the cylinder which has been vacuum-purged can't pressurize itself.
I have concluded that as the user, it is my responsibility to monitor the tank condition, track the certification date, and check that it is not overfilled.