Lochinvar SMART SYSTEM 502 - 2072 - Manual (Page 32)

3
Troubleshooting
32
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 31 of this manual.
- Bad display board. • Replace board.
- Bad main control board. • Replace main control board.
No Burner
Operation
- Main control board temperature set point
satisfied.
• Review temperature setting.
- Remote thermostat satisfied. • Review remote thermostat setting.
- Outside air temperature above Warm
Weather Shutdown (WWSD) set point for
main control board.
• Check location of outside air sensor. Check
resistance of outdoor air sensor and compare to Table
3D on page 33 of this manual.
- Unit locked out on fault.
• Consult display for specific fault. Refer to fault
descriptions on pages 35 - 42 of this manual for
corrective
actions.
Unit Does Not
Modulate to
100%
- Ramp delay active.
• Check ramp delay parameter settings. Optional PC
software required.
• Turn ramp delay feature off. See page 18 of this
manual for instructions on how to turn this feature off.
- 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, Water Heater and Pool Service Manual