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3 Troubleshooting
34
FAULT CAUSE CORRECTIVE ACTION
No Display
- No 120 VAC supplied to unit.
• Check external line switch, fuse, or breaker.
• Check position of ON/OFF switch. Turn switch to the
ON position.
• Check 120 VAC through the ON/OFF switch. No
voltage through switch, replace switch.
- Bad wiring connection.
• Check wiring harness connection between the display
board and the main control board. Connect the harness
at both points.
- Blown fuse.
• Replace fuse F6 on the main control board, see
FIG. 3-1 on page 33 of this manual.
- Bad display board. • Replace board.
- Bad main control board. • Replace main control board.
No Burner
Operation
- Main control board temperature setpoint
satisfied.
• Review temperature setting.
- Remote thermostat satisfied.
• Review remote thermostat setting.
- Outside air temperature above Warm
Weather Shutdown (WWSD) setpoint for
main control board.
• Check location of outside air sensor. Check
resistance of outdoor air sensor and compare to Table
3C on page 35 of this manual.
- Unit locked out on fault.
• Consult display for specific fault. Refer to fault
descriptions on pages 37 - 43 of this manual for
corrective actions.
Unit Does
Not Stage to
100%
- Boiler controlled by BMS.
• Check BMS parameter settings. Optional PC
software required.
- Outlet temperature too high.
- Delta T too high.
Table 3A Troubleshooting Chart - No Display
Copper-fin II/IIE Boiler and Water Heater Service Manual