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FLUE THERMOSTAT OPEN?
HEATING SEQUENCE OF OPERATION
NORMAL HEATING MODE
ABNORMAL HEATING MODE
BURNER CONTROL LED: SLOW FLASH RATE
THERMOSTAT CALLS FOR HEAT (W1)
BURNER CONTROL LED: FAST FLASH RATE
FLAME OFF?
CONTROL SELF–CHECK OKAY?
HIGH LIMIT SWITCH CLOSED?
PRESSURE SWITCH(ES) OPEN?
COMBUSTION AIR BLOWER ON AT HIGH SPEED (W1 CALL S101
CLOSED OR W2 CALL) OR LOW SPEED (W1 CALL S101 OPEN)?
CORRECT PRESSURE SWITCHES CLOSED? (S72–LOW & S102–HIGH FIRE)
PREPURGE (30 seconds)
IGNITION TRIAL (7 seconds) –– OPEN MAIN GAS VALVE.
INCREMENT TRIAL REGISTER. HAS FLAME BEEN REGISTERED
WITHIN 7 SECONDS?
“HEAT” LED–DS2 LIT. 45 SECONDS TIME DELAY FOR FAN ON
ACTIVATED ON VSP2.
FLAME SENSE OKAY?
FLAME CONTINUOUSLY CHECKED?
ROLLOUT SWITCHES CLOSED?
HIGH LIMIT SWITCH CLOSED?
CORRECT PRESSURE SWITCH(ES) CLOSED?
THERMOSTAT OPENS (W1)
BURNER CONTROL LED: SLOW FLASH RATE
COMB. AIR BLOWER OFF (5 sec. delay)
FAN OFF (After selected 90, 150, 210, or 270 delay)?
YES
YES
YES
YES
YES
YES
YES
YES
YES
LOCKOUT: MAIN VALVE OFF
COMB. AIR AND SYSTEM FANS ON
RESET THERMOSTAT
BURNER CONTROL LED: 5 flash if flame sensed with valve off
BURNER CONTROL LED: Steady on if control board failure
NO
NO
CHECK TO SEE IF MAIN VALVE IS OFF.
SEQUENCE HOLDS UNTIL HIGH LIMIT CLOSES.
BURNER CONTROL LED: 4 flashes.
NO
CHECK TO SEE IF MAIN VALVE IS OFF.
SEQUENCE HOLDS UNTIL PRES. SWITCH(ES) OPENS.
BURNER CONTROL LED: 3 flashes.
CHECK TO SEE IF MAIN VALVE IS OFF.
SEQUENCE HOLDS UNTIL CORRECT PRES. SWITCH(ES) CLOSES.
BURNER CONTROL LED: Fast flash rate.
MAIN VALVE AND IGNITOR ARE OFF.
INCREMENT TRIAL REGISTER
THREE TRIALS COMPLETED?
NO
NO
IGNITION RESET PERIOD
(COMBUSTION & SYSTEM FANS OFF.
IS 60 MIN. RESET PERIOD COMPLETE?
BURNER CONTROL LED: Fast flash rate.
MAIN VALVE AND IGNITOR OFF.
LOCKOUT: MAIN VALVE OFF.
COMBUSTION AND SYSTEM FANS ON.
RESET OR REPLACE ROLLOUT SWITCH.
BURNER CONTROL LED: 4 flashes.
MAIN VALVE OFF. COMBUSTION & SYSTEM FANS ON.
SEQUENCE HOLDS UNTIL SWITCH CLOSES
BURNER CONTROL LED: 4 flashes for hi limit.
BURNER CONTROL LED: 3 flashes for pressure switch.
SWITCH CLOSED
COMBUSTION FAN ON. SYSTEM FAN OFF.
(AFTER DELAY TO OFF INTERVAL COMPLETED.)
BURNER CONTROL LED: Fast flash rate.
NO
YES
YES
NO
NO
NO
NO
YES
HOT SURFACE IGNITION CONTINUITY CHECK OKAY?
IGNITOR WARM-UP PERIOD (35 seconds)
YES
LOCKOUT: MAIN VALVE OFF; COMBUSTION AND SYSTEM
FANS OFF. BURNER CONTROL LED: 6 flashes.
RESET THROUGH THERMOSTAT.
NO
FAN ON (LOW FIRE = LOW SPEED / HIGH FIRE = HIGH SPEED) –
TERMINAL ACCA & ACCH ACTIVATED; ON VSP2 “ON/OFF”
LED–DS3 LIT, “CFM” LED–DS4 BLINKS ONCE FOR EVERY 100 CFM.
FAN ON HEATING SPEED
THERMOSTAT CALLS FOR W1 ONLY.
COMBUSTION AIR BLOWER SWITCHES TO LOW SPEED.
GAS VALVE SWITCHES TO LOW FIRE.
FAN SWITCHES TO LOW SPEED, ON VSP2 “HEAT” LED–DS2
IS OFF, ONLY “ON/OFF” LED–DS3 IS LIT. “CFM” LED–DS4
BLINKS ONCE FOR EVERY 100 CFM.
NO
NO
FLAME SENSE OKAY?
FLAME CONTINUOUSLY CHECKED?
ROLLOUT SWITCHES CLOSED?
HIGH LIMIT SWITCH CLOSED?
PRESSURE SWITCHES CLOSED? (S72)
YES
YES
YES
LOCKOUT: MAIN VALVE OFF. COMBUSTION AND SYSTEM
FANS ON. RESET OR REPLACE ROLLOUT SWITCH.
BURNER CONTROL LED: 4 flashes.
MAIN VALVE OFF. COMBUSTION & SYSTEM FANS ON.
SEQUENCE HOLDS UNTIL SWITCH CLOSES.
BURNER CONTROL LED: 4 flashes for hi limit.
BURNER CONTROL LED: 3 flashes for pressure switch.
COMBUSTION AIR BLOWER AT HIGH SPEED.
GAS VALVE AT HIGH FIRE.
MAIN VALVE AND IGNITOR OFF.
SWITCH CLOSED
COMBUSTION FAN ON. SYSTEM FAN OFF.
(AFTER DELAY TO OFF INTERVAL COMPLETED.)
BURNER CONTROL LED: Fast flash rate.
YES
YES
YES
YES
NO
NO
NO
NO
NO
COMBUSTION BLOWER SWITCHES TO HIGH SPEED.
PRESSURE SWITCH S102 CLOSED?
GAS VALVE SWITCHES TO HIGH FIRE.
INDOOR FAN SWITCHES TO HEAT SPEED.
YES
THERMOSTAT CALLS FOR W2
SEQUENCE HOLDS UNTIL PRESSURE SWITCH CLOSES.
NO
NO
