Open Circuittrouble
Fire-Lite MS-9200UDLS: Open Circuit
Fire-Lite MS-9200UDLS·1 view·0 field notes
What This Code Means
This condition indicates that the control panel has detected a break in the wiring or a missing end-of-line resistor on a Notification Appliance Circuit (NAC).
Common Causes
- 1Broken or disconnected field wiring in the NAC loop
- 2Missing 4.7 kΩ End-of-Line (EOL) resistor
- 3Loose terminal connection at TB3 or TB4
- 4Incorrect EOL resistor value used for circuit supervision
Resolution Steps
Inspect the Notification Appliance Circuit (NAC) wiring for physical breaks or loose connections at the terminal blocks. Verify that a 4.7 kΩ, 1/2 watt End-of-Line resistor (P/N 71252) is correctly installed at the end of the circuit. Use the panel's Read Status function to check the NAC voltage; a reading of -2.3 to -2.5 VDC confirms an open circuit condition.