Service Port HVAC: Description and Operation

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.

The high side fitting is the largest. Special couplings are required for both the high side and low side service ports:
^ Rotunda R-134a Low Side Quick Disconnect 176-R0036 or equivalent.
^ Rotunda R-134a High Side Quick Disconnect 176-R0037 or equivalent.
Always install the A/C charging valve cap on the service access gauge port valves after servicing the refrigerant system.