Thermo Products CMA1-50N, CMA2-75N service manual V.Starting The Unit A. Sequence Of Operations

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

V.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
	ADEQUATE DIFFERENTIAL PRESSURE,
				CONTACTS CLOSE

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

START
	AFTER IGNITOR WARM-UP,
TRIAL
	THE GAS VALVE IS
FOR
	ENERGIZED TO OPEN
IGNITION

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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