If it does not seat easily

The 3/8" SAE Flare side relies on metal-to-metal contact for its seal and does not require sealant

by replacing a green or blue spring with this orange 143-62-021-18 spring

Using a standard multimeter

KMC Controls HPO-5114 Diaphragm If it does not seatThe KMC Controls HPO 5114 is a specialized replacement actuator diaphragm engineered for pneumatic control systems. Designed specifically for technical compatibility with the KMC VCP 11, VCP 21, and VCP 34 series pneumatic damper actuators, this component is essential for maintaining precise pressure modulation. In high demand HVACR environments, the HPO 5114 diaphragm ensures consistent stroke performance and reliable seal integrity, preventing air