Lochinvar 402 - 2072 Fault, Cause, Corrective Action, Troubleshooting, No Display, No Burner

Copper-fin II/IIE Boiler and Water Heater Service Manual

3 Troubleshooting

Table 3A Troubleshooting Chart - No Display

FAULT	CAUSE		CORRECTIVE ACTION
		•	Check external line switch, fuse, or breaker.
		• Check position of ON/OFF switch. Turn switch to the
	- No 120 VAC supplied to unit.		ON position.
		• Check 120 VAC through the ON/OFF switch.				No
			voltage through switch, replace switch.
No Display		• Check wiring harness connection between the display
	- Bad wiring connection.		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.
	- Main control board temperature setpoint	•	Review temperature setting.
	satisfied.
	- Remote thermostat satisfied.	•	Review remote thermostat setting.
No Burner
	- Outside air temperature above Warm	•	Check location of outside air sensor.		Check
Operation
	Weather Shutdown (WWSD) setpoint for		resistance of outdoor air sensor and compare to Table
	main control board.		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	- Boiler controlled by BMS.
		• Check BMS parameter settings.		Optional PC
Not Stage to	- Outlet temperature too high.
			software required.
100%
	- Delta T too high.

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