Page 24
Troubleshooting: Heating Sequence of Operation (Continued)
HEATING SEQUENCE OF OPERATION
PRESSURE SWITCH CLOSED WITHIN
2.5 MINUTES?
GAS VALVE OFF. COMBUSTION AIR INDUCER
OFF. INDOOR BLOWER OFF. UNIT WILL RETRY
AFTER 5-MINUTE WAIT PERIOD.
STATUS ERROR CODE 2 + 3.
YES
NO
15-SECOND COMBUSTION AIR INDUCER
PRE-PURGE INITIATED BY CLOSED FIRST-STAGE
PRESSURE SWITCH (or 15 SECOND
INTER-PURGE PERIOD.)
STATUS LED -- HEARTBEAT.
IGNITOR WARM-UP
(20 SECONDS)
STATUS LED -- HEARTBEAT.
IS VOLTAGE ABOVE 170 VOLTS?
NO
COMBUSTION AIR INDUCER OFF, IGNITER OFF.
SIGNAL HOLDS UNTIL VOLTAGE RISES ABOVE 170
VOLTS. STATUS ERROR CODE 4 + 8.
YES
NO
COMBUSTION AIR INDUCER STAYS ON, IGNITER
OFF, GAS VALVE OFF. RETRIES IGNITION 4
MORE TIMES, GOES INTO 1 HR. WATCHGUARD
MODE STATUS ERROR CODE 4 + 7.
YES
AT END OF IGNITOR 20 SECOND WARM UP
PERIOD, 4-SECOND TRIAL FOR IGNITION.
GAS VALVE OPENS, IGNITOR ENERGIZED DURING
4-SECOND TRIAL UNTIL FLAME SENSED.
YES
4-SECOND FLAME STABILIZATION PERIOD.
FLAME RECTIFICATION CURRENT CHECK
CAN FLAME BE PROVEN WITHIN 4
SECONDS AFTER GAS VALVE OPENS?
(
u
0.20 microamps)
GAS VALVE OFF. COMBUSTION AIR
INDUCER ON. INDOOR BLOWER OFF.
STATUS LED -- HEARTBEAT.
HAS CONTROL FAILED TO SENSE
FLAME FOR FIVE CONSECUTIVE TRIES
DURING A SINGLE HEAT DEMAND?
YES
THERMOSTAT CALLS FOR HEAT
STATUS LED - HEARTBEAT
(Refer to box A on previous page)
YES
FLAME PRESENT?
NO
HAS CONTROL RESET IGNITION SEQUENCE
FOUR (4) TIMES?
WATCHGUARD MODE.
STATUS ERROR CODE 4 + 3.
NO
CONTINUED ON NEXT PAGE
YES
NO
NO
CONTINUED
IS IGNITOR INTACT AND CONNECTED?
WATCHGUARD MODE. GAS VALVE OFF,
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF.
STATUS ERROR CODE 4 + 1.
IS 60-MINUTE RESET PERIOD COMPLETE?
NO
YES
