ActronAir Reversing Valve reverses refrigerant flow to switch between cooling and heating modes on WRC series wall split systems on compatible ActronAir R22 split ducted and wall split systems. A leaking reversing valve causes system capacity loss in both modes and warm liquid return when it should be hot -- diagnose with refrigerant circuit temperature measurements before replacing. Isolate power and recover all refrigerant before replacing any refrigerant circuit valve components.