I have a service call that has stumped me and another hvac contractor. Carrier split system, heat pump. The low voltage is playing games on us. with the system off em. is showing 24olts at the thermostat. up in the attic at the air handler when I break the two Y wires it shows 12olt on each wire when they are not together. At the condenser I have all the low voltage dissconected. I have ohmed out the wires and there is no short. in short when the thermostat satisfiys there is still 24 volts going to the condenser what can it be? this is the 3rd t-stat this contractor has changed.