Siemens UL 489 Operating Instructions Manual page 233

12.8.2.4 Removing the Contact Blocks
MOC Reliability
May cause intermittent signaling.
All four contact blocks, whether wired or not, must be installed into the MOC assembly to ensure reliable operation.
The contact blocks must be removed in order to access the terminals for wiring. The contact blocks should be removed by applying a small
amount of outward pressure with a thin blade screwdriver, in the area shown in Figure 6.
Contact block damage.
May cause loss of signaling.
Do not over-extend the feet of the contact block when reinstalling into the MOC assembly.
NOTICE
Figure 6
NOTICE
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