Crest Audio FBN0751 Service Manual page 45

3
Troubleshooting
Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
FAULT
Transition Gas
Valve / Relay
Failure
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART TOUCH display
to reset.)
Manual Reset
High Limit Open
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART TOUCH display
to reset.)
Fan Speed Low
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART TOUCH display
to reset.)
(continued)
DESCRIPTION
The main control board did not detect the
transition gas valve.
The outlet water temperature has exceeded
the setting of the high limit.
The actual fan RPM is 30% lower than what
is being called for.
Blown fuse.
CORRECTIVE ACTION
• Check the wiring harness connection at the gas valve
and the control board.
• Replace the wire harness.
• Replace the gas valve.
• Replace the 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 5 - Hydronic Piping of the
Crest Installation and
for the proper piping methods for the Crest boiler.
• Check voltage to boiler pump motor on a call for
heat. If voltage is not present, check wiring back to
the main control board.
• Replace the pump relay if necessary.
• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.
• If the system pump is a variable speed pump, ensure
that the system flow is not less than the boiler flow.
• If operating on either an inlet or system supply sensor,
check temperature setting of the main control board.
• If the high limit has tripped, check setting of the
device and the MRHL set point.
• Check resistance of water sensors and compare to
Table 3B on page 39 of this manual.
sensor if necessary.
• Replace high limit (if equipped).
• Replace main control board.
• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting of the
Crest Installation and
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 fuse F2 on the control board, see page 37
of this manual.
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