An SLC Open Fault indicates a break in the Signaling Line Circuit wiring, preventing the panel from detecting continuity through the loop. This fault typically appears when the SLC is configured for NFPA Style 6 or 7 (redundant loop) and a wire is broken or disconnected [1].
To clear the fault:
Inspect the SLC terminal block (TB8) on the main circuit board or SLC-2 expander for loose or disconnected wires (Page 3, 42) [1].
Trace the field wiring to locate physical breaks, open junction boxes, or devices removed from their bases.
Ensure the wiring configuration matches the programmed NFPA Style (4, 6, or 7) (Page 2) [1].
Verify the loop resistance does not exceed 40 ohms (Page 3) [1].
Once the physical continuity is restored, the panel will automatically record a "clear trouble" message; use the System Reset key to clear the display (Page 130) [1].
