Lochinvar SNA285-125 Service Blk, Low 24 VAC, Watch Dog Error, Write EEProm, CRC Parameters

TM

Installation & Service Manual

13 Troubleshooting (continued)

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

FAULT	DESCRIPTION	CORRECTIVE ACTION
		• Establish a draw to remove HW heat from the
		water heater.
		• Verify that the system is full of water and that all air
		has been properly purged from the system.
		• Verify that the water heater is piped properly into the
		heating system. Refer to Section 6 - System Piping
		for the proper piping methods for the Shield water
Service Blk		heater.
	While the unit is in Service Mode, the outlet
		• Check 120 VAC to the water heater pump motor on
	temperature has exceeded 185°F.	a call for heat. If voltage is not present, check the
		wiring back to the main control board. Replace the
		main control board if necessary.
		• If 120 VAC is present on a call for heat and the water
		heater pump is not operating, replace the pump.
		• Verify that the water heater pump is set to the proper
		speed or that the water heater pump is the proper
		size. Reference Section 6 - System Piping for water
		heater pump specifications.
		• Check 120 VAC supply to the transformer.
		• Check wiring connections at the low voltage terminal
Low 24 VAC	120 VAC input to the main control board has	strip.
	dropped below 80 VAC.
		• Check the wire size/length to remote devices.
		• Replace the transformer.
Watch Dog Error	The main control board has detected an	• Replace the main control board.
	internal fault.
Write EEProm	The main control board has detected an	• Replace the main control board.
	internal fault.
CRC Parameters	The main control board has detected an	• Replace the main control board.
	internal fault.

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