ActronAir Reversing Valve Coil activates the reversing valve to switch between cooling and heating on CRS series wall split systems on compatible ActronAir R22/R410A split ducted and wall split systems. A failed coil leaves the reversing valve in a fixed position -- confirm coil failure by checking 240VAC is present at the coil terminals during a mode-switch command before replacing. Isolate power and recover all refrigerant before replacing any refrigerant circuit valve components.