Lochinvar SNA400-125 Troubleshooting, Fault, Description, Corrective Action, Manual Reset, Open

TM

Installation & Service Manual

13 Troubleshooting

Table 13E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater Interface

FAULT	DESCRIPTION	CORRECTIVE ACTION
	The outlet water temperature has exceeded	• Verify that the system is full of water and that all air
	the fixed setting of the manual reset high	has been properly purged from the system.
	limit.	• Verify that the water heater is piped properly into the
		heating system. Refer to Section 6 - System Piping
Manual Reset		for the proper piping methods for the Shield water
		heater.
High Limit		• Check 120 VAC to water heater pump motor on a call
(will require a manual
		for heat. If voltage is not present, check wiring back
reset once the condition
		to the main control board.
has been corrected. Press
the RESET button on the		• Replace the main control board if necessary.
display to reset.)		• If 120 VAC is present on a call for heat and the water
		heater pump is not operating, replace the pump.
		• Check resistance of water sensors and compare to
		Table 13B on page 60 of this manual. Replace
		sensor if necessary.
	The actual fan RPM is 30% lower than what	• Vent/air intake lengths exceed the maximum allowed
	is being called for.	lengths.	Refer to Section 2 - General Venting for
		proper lengths.
Fan Low
		• Check for obstruction		or blockage in the vent/air
OR
		intake pipes or at terminations.
Fan Speed Low
(will require a manual		• Check the wiring connections at the fan and at the
reset once the condition		main control board.
has been corrected. Press		• Replace the fan.
the RESET button on the
display to reset.)		• Replace the main control board.
	Blown fuse.	• Replace fuse F4 on the control board, see page 58
		of this manual.
		• Check the wiring connections to switch. Wires
		should be connected to the common and normally
		closed terminals.
		• Air intake lengths exceed the maximum allowed
		lengths. Refer to Section 2 - General Venting for
APS		proper lengths.
		• Check	for obstruction or blockage in the air
Open
		intake pipes or at terminations.
(will require a manual
reset once the condition	Air pressure switch contacts are open.	• Check reference hoses connected to the air pressure
has been corrected. Press		switch for blockage or obstruction.
the RESET button on the		• Inspect	the burner.	Reference page 56 of this
display to reset.)
		manual for removal and cleaning procedures.
		Replace if necessary.
		• Inspect the heat exchanger. Reference page 57 of
		this manual for removal and cleaning procedures.
		Replace if necessary.
		• Faulty air pressure switch. Replace switch.

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