Service Manual

3 Troubleshooting
36
Service Manual
Table 3F (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
FAULT DESCRIPTION CORRECTIVE ACTION
Fan High
OR
Fan Speed High
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART SYSTEM display
to reset.)
The actual fan RPM is 30% higher than what
is being called for.
• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 3 - General Venting of the
Knight XL Installation and Operation Manual for
proper lengths.
• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.
• Check the wiring connections at the fan and at the
main control board.
• Replace the fan.
• Replace the main control board.
Sensor Open
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART SYSTEM display
to reset.)
Either the inlet water or outlet water
temperature sensor has been disconnected.
• Check the sensors and their associated wiring.
Repair or replace the sensor or wiring if damaged.
• Measure the resistance of the sensors and compare
the resistance to the tables on page 30 of this
manual.
• Replace the sensor if necessary.
Sensor Shorted
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART SYSTEM display
to reset.)
Either the inlet water or outlet water
temperature sensor has been shorted.
• Check the sensors and their associated wiring.
Repair or replace the sensor or wiring if damaged.
• Measure the resistance of the sensors and compare
the resistance to the tables on page 30 of this
manual.
• Replace the sensor if necessary.
Aux. Proving
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART SYSTEM display
to reset.)
An optional remote proving switch is not
making.
• Check function of remote devices.
• Check for loose or misplaced jumper if auxiliary
proving switch is not installed.
Tank Open
Sensors equipped with an internal limit (such
as the Lochinvar Squire
®
Indirect Tank), the
limit has opened due to temperature (195°F)
or the sensor has become disconnected.
• Check the tank temperature.
• Repair or replace the sensor wiring if damaged.
• Replace the sensor if necessary.