Lochinvar SNA285-125 Description, Troubleshooting, Fault, Corrective Action, Flame, Sequence

TM

Installation & Service Manual

13 Troubleshooting

Table 13E Troubleshooting Chart - Fault Messages Displayed on Water Heater Interface

FAULT	DESCRIPTION	CORRECTIVE ACTION
Flame		• Check supply voltage for proper polarity.
Sequence		• Check external wiring for voltage feedback.
(will require a manual	The flame detector circuit is seeing a flame	• Check the flame rod and make sure it is clean.
reset once the condition	signal while no flame is present.
has been corrected.		• Check the internal wiring for bad connections.
Press the RESET button		• Replace main control board.
on the display to reset.)
		• Inspect spark electrode and associated wiring for
		damage and connection. Reference page 56 of this
		manual for removal and cleaning procedures.
		Replace if necessary.
		• Check for proper electrical grounding of the unit.
		• Check incoming supply gas pressure. Natural gas
		pressures should be between 4 - 14 inches w.c. and
		LP gas pressures should be between 8 - 14
		inches w.c. Refer to Section 7 - Gas Connections for
		detailed information concerning the gas supply.
		• Verify that the plastic hose from the gas valve to the
		air inlet is connected and is not damaged.
		• Verify that the vent/air intake pipes are correctly
		installed and that there are no obstructions.
		• Check for 24 VAC to the gas valve at the 2-pin
		connection on the side of the main control board
No Flame Ign		during the ignition attempt. If no voltage is present,
		replace the main control board.
(will require a manual		• If 24 VAC is present at the main control board, check
reset once the condition	The unit has failed to prove main burner
has been corrected.	ignition after four (4) attempts.	the wiring between the main control board and the
		gas valve. Replace the wiring if necessary. Do not
Press the RESET button
		disconnect the wiring from the gas valve and attempt
on the display to reset.)
		to measure voltage at that point. The main control
		board can detect if the gas valve is not connected and
		will display the GV / Relay Fail fault.
		• If 24 VAC is present, check the outlet of the valve to
		ensure the valve is flowing gas. With a manometer
		connected to the outlet tap of the gas valve, when the
		unit is in the prepurge period, there should be a
		negative pressure present. When the valve is
		energized a change in pressure should occur. If the
		pressure change does not occur, the gas valve is not
		opening. Replace the gas valve.
		• Inspect flame sensor and associated wiring.
		Reference page 56 of this manual for removal and
		cleaning procedures. Replace if necessary.
		• Inspect the burner. Reference page 56 of this manual
		for removal and cleaning procedures. Replace if
		necessary.
		• Replace the main control board.

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