Crest Audio FBN0751 Service Manual page 50

3
Troubleshooting
Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
FAULT
IO Expander Out
Error
The control board detected an internal fault.
Wrong
The personality plug does not match the
Personality Plug
personality plug value stored in memory.
Air Metering
Valve Stuck
Closed
The air metering valve did not open when
(will require a manual
needed.
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
Air Metering
Valve Stuck
Open
The air metering valve did not close when
(will require a manual
needed.
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
A problem was detected with measuring one
Failure ADC
or more temperature sensors.
Controller
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
The control board has detected an internal
fault.
50
DESCRIPTION CORRECTIVE ACTION
• Turn the 120V power OFF. Wait 15 seconds, then turn
the 120V power back ON.
• Replace the control board.
• Remove the lower front jacket and compare the
personality plug value shown on the display with the
value on the personality plug label. If the two values
match, accept the new personality plug value.
• Check the connections at the personality plug
connector.
• Check the voltage at connector X6, pin 13 at the start of
PrePurge. If not 24VAC, replace the control board.
• Check the wiring between the control board and the air
metering valve.
• Replace the air metering valve.
• Replace the control board.
• Check the slide switch on the inside of the air metering
valve actuator.
• Check the voltage at connector X6 pin 13 during the last
part of PrePurge. If 24VAC, replace the control board.
• Check the wiring between the control board and the air
metering valve.
• Replace the control board.
• Check all connections between the temperature sensors
and the control board. Make sure all connections are
dry and secure.
• Connect a PC to the control board and open the Status
window. Look for temperature readings that are jumping
by more than 1°F.
• Check the resistance of all sensors (see page 39).
• Replace the control board.
• Turn the 120V power OFF. Wait 15 seconds, then turn
the 120V power back ON.
• Replace the control board.
Service Manual