Living here just north of Pittsburgh, in the Allegheny valley, we have observed two mornings, this week, with mid 30 temperatures. Because of the threat of an early freeze, I decided to winterize my 'pod now. (I usually try to err on the side of caution.)
I drained the water lines and all four tanks, blew out the water lines. and pumped antifreeze through the system, to protect both the system itself and the P-traps. Just as I was finishing wiping up the splashed antifreeze, the propane alarm sounded. Even after resetting several times, it would not stop until I opened the door, opened the roof vent, and turned on the fan.
The propane tank has been turned off for about 6 six weeks, no candles, torches, or lanterns were burning anywhere inside or outside of the 'pod. The black tank has been drained and flushed for about six weeks also, so there was little or no methane gas available either.
Could the "fumes" from the Propylene Glycol an ethyl alcohol based antifreeze have triggered the alarm? I never had this problem before, any guesses?