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All installations and services must be performed by qualified service personnel.
34
START
TRIAL
FOR
IGNITION
START
CONTINUOUS SAFE OPERATION CHECK
IF FLAME SIMULATION CONDITION
PRESENT OR ROLL-OUT SWITCH OPENS, SYSTEM
ENERGIZES INDUCER FAN FOR 15 SECONDS AND CIRCULATOR BLOWER AT
HEATING SPEED UNTIL SITUATION CORRECTION
THERMOSTAT CALLS FOR
HEAT, CONTACTS CLOSE
POWER INTERRUPTION
SYSTEM SHUTS OFF,
RESTARTS WHEN POWER
IS RESTORED.
PRESSURE SWITCH SENSES
ADEQUATE DIFFERENTIAL PRESSURE,
CONTACTS CLOSE
CONTROL BOARD ENERGIZED,
INDUCER ENERGIZED
POWER IS APPLIED TO
THE SILICON NITRIDE
IGNITOR. IGNITOR
WARM-UP IS 20 SECONDS.
AFTER IGNITOR WARM-UP,
THE GAS VALVE IS
ENERGIZED TO OPEN
FLAME MUST BE DETECTED
WITHIN 4 SECONDS IF
FLAME IS DETECTED, THE
DELAY-TO-FAN-ON TIME
BEGINS (45 SECONDS)
IF FLAME IS NOT DETECTED, THE
GAS VALVE IS DE-ENERGIZED,
THE IGNITOR IS TURNED OFF AND
THE CONTROL BOARD CONTROL GOES
INTO "RETRY" SEQUENCE.
PRESSURE SWITCH SENSES
NEGATIVE PRESSURE(NO DRAIN BLOCKAGE)
CONTACTS CLOSE
(CDB1 SERIES ONLY)
IV. STARTING THE UNIT
A. SEQUENCE OF OPERATIONS
AT ANY TIME THE
GAS VALVE IS
NOT ENERGIZED