Troubleshooting – Lochinvar Shield SNR150-100 User Manual
Page 63
63
13
Troubleshooting
(continued)
Table 13A Troubleshooting Chart - No Display
FAULT
CAUSE
CORRECTIVE ACTION
No Display
- No 120 VAC supplied to unit.
• Check external line switch, fuse, or breaker.
• Check wiring harness connection between display
board and main control board. Connect harness at both
points.
- Bad display board.
• Replace board.
- Bad main control board.
• Replace the main control board.
- Blown fuse.
• Replace fuse F3 on the main control board, see
page 62 of this manual.
No Burner
Operation
- Tank temperature set point satisfied.
• Review temperature setting.
- Unit locked out on fault.
• Consult display for specific fault. Refer to fault
descriptions on page 66 of this manual for corrective
actions.
Unit Does
Not Modulate
Above 50%
- Flue sensor open.
• 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 13C on page 64 of this manual.
Installation & Service Manual
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