I have installed a new controller(old one died)on my reverse cycle airconditioner(APAC Carrier Sundowner S18). I'm in Australia and I think you call these heat pumps? It works fine on cooling. But on heating it will reach set point and cut out. When temperature lowers to restart only the evaperator fan starts. On investigation when it reaches heating set point the evaperator fan cuts out, but the compressor keeps running for 30 seconds or so then it shuts down. Using my multimeter the compressor and reversing valve both have 24VAC current on them still. I assume the safety system is shutting down compressor not the controller. It won't restart even if left for an hour or more. If I turn off at the controller it still only restarts the evaperator fan. If I turn off the main power switch and leave it for 5 minutes it will restart correctly. I assume it resets the system. I think the controller settings aren't correct. I have had Aircond tech look at it. He told me the circuit board was u/s but I don't have confidence in him(expensive guess work I think). If the controller is still powering the compressor and the safety system is shutting it down, then the circuit board can only do what it is told to do. I'm sure the controller settings aren't correct. PLEASE, please all help gratefully accepted