I've got a problem with one of my Daikin multi-zone heat pumps. My house has 4 of these units feeding A/C to 12 individual units throughout my house. Anyways, I noticed that 3 of my units have quit blowing cold air and they are all connected to the same heat pump. (The in-house units have their own power and will just run the fan even if the heat pump isn't working..) I have isolated which one of my 4 heat pumps isn't functioning. I noticed that it looks like the compressor itself isn't turning on. The fan on the unit is not turning on either. I have checked the fuses and the breakers for the heat pump and they are all ok. Could this simply be a refrigerant problem? If the unit is low on freon, will it turn on? Is it like an automobile compressor where the A/C clutch won't engage when the freon is low? I am selling the place in a few months probably and don't want to go through the expense of a new unit if I don't have to. (I am going to offer to pay for a homeowners warranty on the house anyways...) Any ideas? Also, I'm pretty sure the unit is around 16 years old.