Originally Posted by DKB_SATX
Gene: The modern ones may cycle the compressor before getting down to the set temperature, but I'm guessing that unless it detects something wrong (over- or under-temperature on some sensor, etc) it'll run the compressor full tilt until it gets down to the set point. I'm certain my old one works that way.
I don't know why they would cycle the compressor as described, but it could happen. Maybe it is good to rest the compressor periodically for short periods. We have a newer thermostat (2007) which does more things and can be set as low as 40˚. We leave the fan on whenever we are using he A/C and I don't usually notice when the compressor cycles because I've learned to ignore it. Besides, when setting up, no one is sitting in the trailer counting cycles.
So long as we are talking about A/C, several things come to mind—why are RV A/C's noisier than window units at home? Maybe it is because of the confined space with many reflective surfaces. Second, why do they cost so much more than residential window units? And this reminds me of something I read once—horizontal furnaces used in condos and fit in the ceiling, wear out faster than a regular vertical furnace sitting on a floor; does this apply to RV A/C's? Why hasn't anyone designed an RV A/C that sits in the sidewall, like the fridge, and disperses cooled air through some ducts in front, middle and rear?