Lochinvar 81-286 service manual Cont’d, Flame Sequence

Service Manual

3 Troubleshooting (continued)

Table 3-4(continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT	DESCRIPTION	CORRECTIVE ACTION
	The unit has failed to prove main burner	• Verify that the plastic hose from the gas valve to the air
	ignition after four (4) attempts.	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 during
		the ignition attempt. If no voltage is present, replace
		the main control board.
		• If 24 vac is present at the main control board, check
		the wiring between the main control board and the gas
		valve. Replace the wiring if necessary. Do not
		disconnect the wiring from the gas valve and attempt to
Flame Fail Ign		measure voltage at that point. The main control board
		can detect if the gas valve is not connected and will
(cont’d)		display the Gas Valve or Gas Valve Fail fault.
(will require a manual		• If 24 vac is present, check the outlet of the valve to
reset once the condition		ensure the valve is flowing gas. With a manometer
has been corrected.		connected to the outlet tap of the gas valve, when the
Press the RESET button		unit is in the prepurge period, there should be a
on the SMART SYSTEM		negative pressure present. When the valve is
display to reset.)		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 31 of this manual for removal and
		cleaning procedures. Replace if necessary.
		• Inspect and clean the heat exchanger as necessary.
		Reference page 32 of this manual for cleaning
		procedures.
		• Inspect the burner. Reference page 31 of this manual
		for removal and cleaning procedures. Replace if
		necessary.
		• Replace the main control board.
Flame Sequence		• Check supply voltage for proper polarity.
(will require a manual		• Check external wiring for voltage feedback.
reset once the condition	The flame detector circuit is seeing a flame
		• Check the flame rod and make sure it is clean.
has been corrected.	signal while no flame is present.
Press the RESET button		• Check the internal wiring for bad connections.
on the SMART SYSTEM
		• Replace main control board.
display to reset.)

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