Micro Switch used to control drive motor and "ride" the CAM.
Used on several models of Fleck Valves. (old # V7-6B19D8 and new # d3V-16-1C26-K)
2500, 2510, 2750, 2850, 2900, and 9000 / 9100 / 9500. (also used ( 2 of them ) inside front cover of Fleck electronic valves like 5600SE, 5600 SXT).


NOTE: This Switch (10218) when used on Fleck 9000,9100,9500 power head is closer to the Timer Assembly (left side) and the one next to it (16433) will sometimes BREAK on the Fleck 9000, 9100, 9500 power head, and this is a result of the DRIVE MOTOR (18738) running backwards. 
The Drive Motor should be REPLACED to solve this issue.

Also - NOTE: Starting in 2019, Fleck (Pentiar Water Treatment) starting using (2) 16433 switches, and no longer used the switch 10218 on their Power Heads (9000 / 9100 / 9500).

NOTE: Besides physically breaking, this switch can be the problem if the timer completes a full cycle in about 2 minutes and starts again ( never stopping at any of the regeneration cycle positions ).
Two are used on the Fleck 5600SE or 5600SXT Valves behind circuit board and "riding" the Cycle Cam.