Lochinvar FTxl 500 Service Manual page 46

3
Troubleshooting
Table 3-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
FAULT
Flue Temp High
Delta T High
Outlet Temp
High
46
DESCRIPTION
The stack temperature has exceeded the set
parameters for the boiler.
The temperature rise across the heat
exchanger has exceeded the set parameters
for the boiler.
Outlet water temperature has exceeded the
maximum outlet water temperature.
Service Manual
CORRECTIVE ACTION
• Inspect the heat exchanger. Reference page 35 of
this manual for the procedure on how to clean the flue
side of the heat exchanger.
• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and
compare to Table 3-2D on page 39 of this manual.
Replace the sensor if necessary.
• Verify that the vent/air intake pipes are properly
installed and that there are no obstructions.
• Replace the main control board.
• 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
FTXL Installation and
for the proper piping methods for the FTXL boiler.
• Check for 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 pump is the proper size.
Section 6 - Hydronic
Installation and Operation
pump specifications.
• 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
FTXL Installation and
for the proper piping methods for the FTXL boiler.
• Check for 120 vac to the 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.
• 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
Installation and Operation Manual for boiler pump
specifications.
• Replace the main control board.
Operation Manual
Reference
Piping of the FTXL
Manual for boiler
Operation Manual
Piping of the FTXL