I know this is pretty basic--but my older Rheem Classic IX (in FL) seems to be operating fine--except it stopped heating and I think, cooling. It seems to be running fine, without any obvious leaking. It just blows the same cool air on either setting. Where should I start? Are there fuses to look for on auxiliary heat? Or coolant that needs a recharge? I don't have the manual and I'm a northern boy so this heat pump is a new experience for me.

Handydude - try looking for a blown fuse first. That seems to be the usual reason why the machine won't work. The fuse at the bottom on the water pump seems to be the likely culprit.

Are you sure the compressor is running ? Or is it just the condenser fan running? Sometime its hard to hear the 2 running at the same time ,except on startup,you`ll hear the compressor start up a second before the fan motor starts,, with a set of manifold guages you can tell by the pressure it builds up and shows on the gauge,, or you can disconnect the power going to the fan ,if you know what you are doing then hear the compressor running (thuis I wouldn`t advise unless you know what you are doing) elect. Bites

Perhaps the compressor isn't running. Hmmm? I remember thinking the unit sounded a little quieter that usual. I'm not there right now so I can't check to be sure. But if so, what would that mean? A fuse? What stops a compressor from running? Power was temporally interrupted to the outside unit to re-run the electrical feed to a new breaker box. But it's hooked up correctly and of course the fan runs. The breakers are all OK too. Is it circumstantial or did something happen then? Is there a re-set button or relay that popped?

Possible reset button,not sure of you make and model,, just look around and see if you find one,there could be a burned wire not sending power to compressor or any of the 3 wires connected to the compressor,, possible bad capactor, or a shot compressor,, It may be time to call out the professionals,, might cost a few $$ but could save you some $$ also just be very careful ,220 volts of electricity is nothing to experiment with