ok. to clarify the gas heating up issue, what happened has to do with heat. co2 is like most other elements. it has 3 phases- solid liquid and gas. if the scale was mechanical, the cold temp shrunk the spring and it was off some. either way there was too much co2 in that bottle. the co2 was going through a phase change. there is a balance in the tank. at say 300 degrees, water would not boil if there was enough pressure to keep it in it's current phase. the same is true for basicly any element, just on a different scale. molecules would have no where to go, and as much would change phase to a gas that could until the amount of gas made enough pressure to keep the liquid from vaporizing. this is vapor pressure, and it changes with temp. the lower the temp, the lower the vapor press., because the molecules move around less. co2 IS more sensitive than other gases in this department. at the temps we live in, it takes less pressure keep it in liquid state. that is why you wouldn't want to fill that same bottle full of nitrogen for example. this is why they don't use compressed regular air.ok. what this means is that at 30 degrees or so F, the molecules are moving slower, so they don't try as hard to become gas, so the vapor press is less.
now for that same amount at a higher temp, the molecules move faster, the vapor press. increases, so more co2 evaporates, and there is more pressure for the same amount. so it was overfilled, and was at the press. it would otherwise be say at, 75 deg. if filled to spec. if properly filled, the burst press of the safety valve would be closer to 175 deg.F this is so if the bottle gets in a fire, it won't heat up enough to explode.
