Lochinvar 400-801 - Manual (Page 45)

3
Troubleshooting
(continued)
45
Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
FAULT DESCRIPTION CORRECTIVE ACTION
Rem Ctrl Flt
External control is cycling too often.
• Check set point of the external control.
• Check the wiring between the external control and the
unit.
• Replace the control.
Parameters
Progr
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART SYSTEM
display
to reset.)
After downloading parameters from a laptop,
the main control board must be reset.
• Press the ENTER/RESET button on the SMART
SYSTEM display panel.
Service Blk While the unit is in Service Mode, the outlet
temperature has exceeded 185°F.
• 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 and Operation
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 Piping of the Knight
XL Installation and Operation Manual for boiler
pump
specifications.
Low 24 vac 120 vac input to the main control board has
dropped below 80 vac.
• 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.
Watch Dog Error The main control board has detected an
internal fault.
• Replace the main control board.
Write EEProm
The main control board has detected an
internal fault.
• Replace the main control board.
CRC Parameters The main control board has detected an
internal fault.
• Replace the main control board.
No Error Stored The main control board has detected an
internal fault.
• Replace the main control board.
Service Manual