Lochinvar 400 - 801 service manual Flame Sequence, Auto Reset, High Limit, Fan Low, Fan Speed Low

Service Manual

3Troubleshooting (continued)

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

FAULT	DESCRIPTION		CORRECTIVE ACTION
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
		• Replace main control board.
SYSTEM display to
reset.)
		• Verify that the system is full of water and that all air
		has been properly purged from the system.
		• Verify that the boiler is piped properly into the heating
		system. Refer to Section 6 - Hydronic Piping of the
		Knight	XL	Installation	and	Operation			Manual
		for the proper piping methods for the Knight XL boiler.
		• Check 120 vac to boiler pump motor on a call for
		heat. If voltage is not present, check wiring back to
		the main control board.
		• Replace the main control board if necessary.
Auto Reset	The outlet water temperature has exceeded	• If 120 vac is present on a call for heat and the boiler
	the setting of the automatic reset high limit.	pump is not operating, replace the pump.
High Limit
		• If the system pump is a variable speed pump, ensure
		that the system flow is not less than the boiler flow.
		• If operating on something other than an outlet sensor,
		check temperature setting of the main control board.
		• If the optional manual reset high limit has tripped,
		check setting of the device.
		• Check resistance of water sensors and compare to
		Table 3-2A on page 35 of this manual. Replace
		sensor if necessary.
		• Replace high limit.
	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 3 - General Venting of the
Fan Low		Knight XL Installation and Operation Manual for
		proper lengths.
OR
Fan Speed Low		• Check	for	obstruction or	blockage		in	the	vent/air
		intake pipes or at terminations.
(will require a manual
reset once the condition		• Check	the wiring connections at			the	fan	and at the
has been corrected.
		main control board.
Press the RESET button
on the SMART		• Replace the fan.
SYSTEM display to
reset.)		• Replace the main control board.
	Blown fuse.	• Replace fuse F2 on the control board, see page 33
		of this manual.
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