Lochinvar KNIGHT 400 Service Manual page 45

3
Troubleshooting
Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
FAULT
Rem Ctrl Flt
External control is cycling too often.
Parameters
Progr
(will require a manual
reset once the condition
After downloading parameters from a laptop,
has been corrected. Press
the main control board must be reset.
the RESET button on the
SMART SYSTEM display
to reset.)
While the unit is in Service Mode, the outlet
Service Blk
temperature has exceeded 185°F.
120 vac input to the main control board has
Low 24 vac
dropped below 80 vac.
The main control board has detected an
Watch Dog Error
internal fault.
The main control board has detected an
Write EEProm
internal fault.
The main control board has detected an
CRC Parameters
internal fault.
The main control board has detected an
No Error Stored
internal fault.
(continued)
DESCRIPTION
Service Manual
CORRECTIVE ACTION
• Check set point of the external control.
• Check the wiring between the external control and the
unit.
• Replace the control.
• Press the ENTER/RESET button on the SMART
SYSTEM display panel.
• Establish a heating load to remove the heat from the
boiler loop.
• 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
Manual for the proper piping methods for the Knight
XL boiler.
• Check 120 vac to the boiler pump motor on 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 boiler
pump is not operating, replace the pump.
• Verify that the boiler pump is set to the proper speed
or that the boiler pump is the proper size. Reference
Section 6 - Hydronic
XL Installation and Operation Manual for boiler
pump specifications.
• Check 120 vac supply to the transformer.
• Check wiring connections at the low voltage
terminal strip.
• Check the wire size/length to remote devices.
• Replace the transformer.
• Replace the main control board.
• Replace the main control board.
• Replace the main control board.
• Replace the main control board.
and Operation
Piping of the Knight
45