Troubleshooting Chart - No Display - Lochinvar Shield SNR200-100 Installation And Service Manual

13
Troubleshooting
Table 13A Troubleshooting Chart - No Display
FAULT
- No 120 VAC supplied to unit.
No Display
- Bad display board.
- Bad main control board.
- Blown fuse.
- Tank temperature set point satisfied.
No Burner
Operation
- Unit locked out on fault.
- Flue sensor open.
Unit Does Not
Modulate
Above 50%
(continued)
CAUSE
Installation & Service Manual
TM
CORRECTIVE ACTION
• Check external line switch, fuse, or breaker.
• Check wiring harness connection between display
board and main
harness at both points.
• Replace board.
• Replace the main control board.
• Replace fuse F3 on the main control board, see
page 58 of this manual.
• Review temperature setting.
• Consult display for specific fault.
descriptions on page 62 of this manual for corrective
actions.
• Verify that the flue sensor is located in the flue outlet.
• Check wiring connections at the flue sensor.
• Check the resistance of the flue sensor and compare
to Table 3C on page 60 of this manual.
control board. Connect
Refer to fault
59