White Rodgers 927 Thermostat User Manual


 
7
SEQUENCE OF OPERATIONS
APPLY POWER TO
APPLIANCE
IS FIELD WIRING
CORRECT?
DISPLAY ERROR CODE
1
OR
2
NO
YES
REQUEST
FOR HEAT
PRESENT?
NO
IS
PRESSURE SWITCH
PROVEN OPEN WITHIN
5
SECONDS?
YES
NO
COMBUSTION
BLOWER ON
YES
IS
PRESSURE SWITCH
PROVEN CLOSED
WITHIN
5
SECONDS?
NO
WAIT FOR PRESSURE
SWITCH TO OPEN
DISPLAY ERROR
NUMBER
3
WAIT FOR PRESSURE
SWITCH TO CLOSE
DISPLAY ERROR
NUMBER
4
PREPURGE
IS
IGNITOR
OKAY?
TURN OFF INDUCER
DISPLAY ERROR CODE
NUMBER
5
NO
IGNITOR ON FOR
WARM-UP TIME
YES
YES
MAIN VALVE OPENS
MAIN
BURNER LIGHTS
AND IS SENSED
DURING TRIAL
FOR
IGNITION
IGNITOR TURNS OFF
YES
NO
IS
FLAME SENSE
LOST?
IS
REQUEST FOR HEAT
SATISFIED?
MAIN VALVE OFF
COMBUSTION
BLOWER OFF AFTER
POST-PURGE DELAY
MAIN VALVE CLOSES
LESS
THAN
3
TRIES
FOR IGNITION?
MAIN VALVE CLOSES
LOST
LESS THAN
3
TIMES?
YES
YES
TURN OFF INDUCER
AFTER POST-PURGE
DISPLAY ERROR
6
ONE HOUR AUTO
LOCKOUT RESET
DELAY
NO
NO
NO
YES
YES
NO
Intelli-Vent™
Sequence of Operation
Please Note:
The control continually monitors
internal circuits and external sensors.
Error codes noted above, and those for
self-diagnostic faults can be found on
pages 8 and 9.
IS
PRESSURE SWITCH
PROVEN OPEN WITHIN
5
SECONDS?
WAIT FOR PRESSURE
SWITCH TO OPEN
DISPLAY ERROR
NUMBER
3
COMBUSTION
BLOWER ON
IS
PRESSURE SWITCH
PROVEN CLOSED
WITHIN
5
SECONDS?
WAIT FOR PRESSURE
SWITCH TO CLOSE
DISPLAY ERROR
NUMBER
4
INTERPURGE
COMBUSTION
BLOWER OFF
YES
NO
NO
YES
YES