Thermo Products CHB1-125N, CHB1-75N, CHB1-100N, CBD1-75N, CBD1-100N, CBD1-125N CDB1 SERIES ONLY

All installations and services must be performed by qualified service personnel.

IV. STARTING THE UNIT

A. SEQUENCE OF OPERATIONS

AT ANY TIME THE				CONTINUOUS SAFE OPERATION CHECK
GAS VALVE IS				IF FLAME SIMULATION CONDITION
NOT ENERGIZED			PRESENT OR ROLL-OUT SWITCH OPENS, SYSTEM
		ENERGIZES INDUCER FAN FOR 15 SECONDS AND CIRCULATOR BLOWER AT
START			HEATING SPEED UNTIL SITUATION CORRECTION
			THERMOSTAT CALLS FOR
			HEAT, CONTACTS CLOSE
	CONTROL BOARD ENERGIZED,
			INDUCER ENERGIZED

			PRESSURE SWITCH SENSES
	PRESSURE SWITCH SENSES
			NEGATIVE PRESSURE(NO DRAIN BLOCKAGE)
ADEQUATE DIFFERENTIAL PRESSURE,
			CONTACTS CLOSE
		CONTACTS CLOSE
			(CDB1 SERIES ONLY)

START

TRIAL

FOR

IGNITION

POWER IS APPLIED TO	POWER INTERRUPTION
THE SILICON NITRIDE	SYSTEM SHUTS OFF,
IGNITOR. IGNITOR	RESTARTS WHEN POWER
WARM-UP IS 20 SECONDS.	IS RESTORED.

AFTER IGNITOR WARM-UP,

THE GAS VALVE IS

ENERGIZED TO OPEN

FLAME MUST BE DETECTED	IF FLAME IS NOT DETECTED, THE
WITHIN 4 SECONDS IF	GAS VALVE IS DE-ENERGIZED,
FLAME IS DETECTED, THE	THE IGNITOR IS TURNED OFF AND
DELAY-TO-FAN-ON TIME	THE CONTROL BOARD CONTROL GOES
BEGINS (45 SECONDS)	INTO "RETRY" SEQUENCE.

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