Eliminates hazardous discharge of refrigerant and oil from high side of system when disconnecting hoses. Prevents freezing hand when disconnecting, especially when servicing heat pumps in cold weather. Automatic shutoff of hose ends permits discharging high side hose through manifold into low side. Automatic full depression of core valves without adjustment, regardless of core position. Coupler halves separately connect to access fitting and hose end, then easy push/pull operation automatically opens or closes system without loss of refrigerant. Simplifies operation of charging critical amount of refrigerant into small systems.