Short Cycling I have a Zoneline 2100 Series that short cyles. It will kick on...fan and compressor, run for a while, then the compressor will shut off and the fan will continue to run for a period of time and then shut off. The unit will be off for a few mins and then the fan kicks on and later the compressor starts up again. It basically does this in heat mode as well. I changed the thermostat out today, thinking that might be the problem but it was not. It will heat and cool properly while it is in operation.

COMPRESSORS HAVE AN INTERNAL T-STAT TO PROTECT THE WINDINGS ... SOME THING IS CAUSING YOUR COMPRESSOR TO RUN "HOT" THIS WILL KICK "IN & OUT" THE COMPRESSOR DURING COLLING OPERATION AND HEAT MODE (IF IT IS A HEAT-PUMP). 1ST THING TO EASILY CHECK IS THE CONDENSOR "OUT-SIDE" COIL. (CLEN BOTH WHILE YOU ARE AT IT). THESE FANS PULL THE AIR IN AND A BLOW OUT THE COIL .... ALL THE DIRT WILL BE ON THE INSIDE. 2ND THING IS THE FAN ITSEL OVER HEATING AN TURNING "OFF" ON ITS OWN "BUILT-IN POTECTION T-STAT". THIS WILL GIVE YOU THE IRRATIC OPERATION YOU ARE DESCRIBEING. I TEND TO THINK IT IS YOUR FAN MOTOR ... EASY TEST. TURN "OFF" EVERYTHING BUT THE FAN. SET IT FOR MANUAL "RUN ALL THE TIME" POSITION. THE FAN SHOULD NOT KICK OFF !!! IF IT DOES YOU FOUND THE PROBLEM. IF IT DOES TURN OFF IT CAN BE A WEAK CAPACITOR. UNITS VARY ON WETHER THE CAPACITOR IS FOR COMPRESSOR/FAN OR HAS A SEPERATE CAPACITOR FOR EACH. CAPACITORS ARE NOT EXPENSIVE. HOPE THAT CAN NARROW YOUR PROBLEM DOWN

I have found that my unit has a 2 min delay module inside the outdoor unit and it was bad which made the unit cycle on and off or just not at all . I fixed that myself after finding the part and it was simple to do .