I have a McQuay 5 ton water source heat pump above a drop ceiling and surrounded by duct work and sprinkler lines so space is tight and vision poor . This unit was controlled by energy management but has been locking out lately . I disconnected the EMS and jumped the unit out with RED , W-1 and G . the unit turns on in heat for about 5 minutes then the reversing valve screams and it goes to cooling , 5 minutes , the scream and back to heat . The install guys did me no favors as I may have to drop the unit to access the controls . Any idea what this might be before I rip the ceiling out ???