SMC Legacy SY Series

What does “-S” suffix indicate in In the Legacy SY Series valve p/n SY5140-5D-S?

he “-S” suffix indicates the valve is an “old style”.

Prior to 2013, SMC did a refresh to Legacy SY Series.  The original pilot assembly was upgraded with a new design for reduced power consumption.   At same time, the main valve body was streamlined to accommodate the new pilot.  These changes *did not* affect the overall fitment of the valves.  New valves are completely backward compatible.  They will mate with the same mounting bases, manifolds, and electrical connectors.  The current design can be easily recognized by a stainless steel cover on the pilot and a BLUE manual override button.  The older design didn’t have the stainless cover, and had an ORANGE override button on the valve body.

The “old-style” valves were offered concurrently during a transition period, and they were distinguished with “-S” suffix.  Today those “-S” part numbers are obsolete (although there may be small amount of residual stock).

Note that the pilot assemblies themselves are NOT interchangeable.  So it’s not possible to repair an older “-S” valve.  The old valve can be directly replaced by same valve p/n without the “-S” suffix.