Have you tried disconnecting and reconnecting the communication cable from the controller to the touchscreen controller? We have daikin units that looss communication between the two that cause the touch screen to become unresponsive but the unit still works normally. For what ever reason even cycling power won't reestablish communication between the two. Only disconnecting and reconnecting the cable re-initializes the comm. We havent been able to find the cause but suspect it is momentary power loses in the building.