Service Port HVAC: Description and Operation

The high-side fitting is the largest. Special couplings are required to connect service equipment to both the high-side and low-side service ports.
^ Quick disconnects must be used to connect a manifold gauge set to the system.
^ Always install the A/C charging valve caps on the service access gauge port valves after servicing the refrigerant system.

The service gauge port valves are either a one-piece or two-piece design:





^ In the two-piece design, the aluminum top portion of the valve is threaded to the bottom part and sealed with an O-ring seal. The valve seal is an integral part of the aluminum fitting piece which must be replaced if the seal leaks.





^ In the one-piece design, the valve is an integral part of the refrigeration line or component. The Schrader-type valve core can be replaced if the seal leaks.