I remember the older roof TOP A/C units would freeze up if the outside temp was near or lower than the A/C temp setting inside. Is that still true about the newer units. Mine kind froze up today so turned it off, turned the fan on "only" and in a short time, the fan was blowing good again (it had gotten really slow flow). I let it just blow for a couple hours and then turned on the A/C unit for cooling and it seemed to be ok. I've turned it off for now, because it is pretty nice out so airing out the inside.