A bit of info what keeps K1 closed.
The CR3, S5-2, S5-3, K8-OL, K8-SC, K1-11, K1-12 path to ground is the latching path that keeps K1 closed when you release S5. When you put S5 in OPEN it breaks this path, K1 opens as well as the K1-11, K1-12 switch in K1.
The other side of the K1 coils gets...