Multi Position Valves and More - Short #293

Multi Position Valves and More - Short #293

From HVAC School - For Techs, By Techs by Bryan Orr

July 7, 2026 · 20 min

About this episode

Bryan discusses multi-position service valves and their advantages over traditional Schrader valves in HVAC applications.

In this short podcast episode, Bryan talks about multi-position service valves and more valve types. Many typical residential systems have brass service valves with a hex cap and Schrader ports; access happens solely through the Schrader ports (where the cores are). Schraders are restrictive and prone to leaking, and they don't have the ability to back-seat or front-seat. In applications where we need that capability, we use multi-position service valves instead. (Note: CoreMax valves have much higher flow rates, but you can't remove the cores except with a highly specialized tool.) Multi-position service valves are common in commercial refrigeration and allow for unrestricted, full-port flow. They do not have spring-loaded cores in the service port. If you treat these valves like Schrader valves, refrigerant WILL come out if it's not back-seated. You adjust the position by turning the stem with a refrigeration service wrench; loosen the packing nut before attempting to turn the stem, as tightening it down will crush the compressible packing material around the rotating stem. Tighten it back down after making your adjustment. These valves also require lots of heat to braze, so we…

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