Corrective Action - Cadet 40-120 Installation And Service Manual

13
Troubleshooting
Table 13-1 Troubleshooting Chart - No Display
FAULT
- No 120 vac supplied to unit.
No Display
- Bad display board.
- Bad main control board.
- Blown fuse.
- Main control board temperature set point
satisfied.
- Remote thermostat satisfied.
No Burner
- Outside air temperature above Warm
Operation
Weather Shutdown (WWSD) set point for
main control board.
- Unit locked out on fault.
Unit Does
Not Modulate
- Flue sensor open.
Above 50%
70
CAUSE
Installation & Service Manual

CORRECTIVE ACTION

• Check external line switch, fuse, or breaker.
• Check wiring harness connection between display
board and main control
harness at both points.
• Replace board.
• Replace the main control board.
• Replace fuse F3 on the main control board, see
page 69 of this manual.
• Review temperature setting.
• Review remote thermostat setting.
• Check location of outside air sensor.
resistance of outdoor air sensor and compare to Table
13-2B on page 71 of this manual.
• Consult display for specific fault.
descriptions on page 73 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 13-2D on page 71 of this manual.
board. Connect
Check
Refer to fault