Propane safety January 07, 2011, 01:27:38 pm Yahoo Message Number: 119484Norm said in part; then dumps the liguid propane into the main tank. I then disconnect the hoses and the portable tank is ready to be refilled.>By INVERTING the tank, it sounds to me like you just completely eliminated the 20% vapor (safety) buffer at the top of the onboard propane tank. Propane going into the RV draws from the top of the onboard tank to ensure that no liquid gets to the regulator, then on to the furnace, stove, water heater, etc. Liquid expansion would push propane back into the auxiliary tank. But if you disconnect the hose from the auxiliary tank, the liquid in the onboard tank, has no where to expand to. Liquid is non compressible, and on a warm day, the onboard tank could rupture the over pressure fitting. This would empty the tank rapidly into the surroundings. Hope there aren't any ignition sources nearby! Normally you fill the tank, with the screw open vent line, open. That wastes vapor to atmosphere, so you can stop filling when liquid starts to come out of the vent. (80% full) Leaving the auxiliary tank upright and not inverted, would prevent this safety hazard. I'll bet there is a label somewhere warning you to not do that! Presumably, an upright tank, would only transfer vapor from the auxiliary tank into the onboard tank. I would think that with the tanks in series, that the onboard tank would quickly empty of liquid, and would only have vapor in it when both tanks ran out. Hope this was helpful. RonB and a '99 TKB named 'Bluebelle'[Non-text portions of this message have been removed]
Re: Propane safety Reply #1 – January 07, 2011, 11:45:42 pm Yahoo Message Number: 119496"By INVERTING the tank, it sounds to me like you just completely eliminated the 20% vapor (safety) buffer at the top of the on-board propane tank"Ron The RV's on-board propane tank's overfill valve should still function normally, preventing the tank from over filling. It should not matter if the tank is filled by gravity or pumped in under pressure, the overflow valve should still work. Either way, the RV's propane tank is being filled with liquid, not vapor.Larry