Thermo Products CMA2-75N, CMA1-50N service manual Main Burner Operation Call For Heat Satisfied

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

MAIN

BURNER

OPERATION

CALL

FOR

HEAT

SATISFIED

AFTER DELAY-TO-FAN-ON

PERIOD ENDS, CIRCULATING AIR FAN IS ENERGIZED AT HEATING SPEED. THE (OPTIONAL) ELECTRONIC AIR CLEANER

AND HUMIDIFIER ARE

ENERGIZED.

WHEN THERMOSTAT IS

SATISFIED, CONTACTS

OPEN AND THE GAS

VALVE IS DE-ENERGIZED.

AFTER PROOF OF FLAME

LOSS, INDUCER STARTS 5 SECOND POST SURGE AND (OPTIONAL)

HUMIDIFIER ARE

DE-ENERGIZED. THE DELAY-

TO-FAN-OFF PERIOD

BEGINS (120 SECONDS)

THE RETRY SEQUENCE PROVIDES A 60 SECOND WAIT BEFORE IGNITION RETRY. RETRY IS ATTEMPTED WITH AN ADDITIONAL 10 SECONDS OF IGNITOR WARM-UP TIME.

IF IGNITION ATTEMPT IS

UNSUCCESSFUL, ONE MORE

RETRY WILL BE MADE

BEFORE THE CONTROL BOARD GOES INTO SYSTEM LOCKOUT.

END

OF CYCLE

	IF FLAME IS DETECTED,
	THEN LOST, THE CONTROL BOARD
	WILL REPEAT THE INITIAL IGNITION
	SEQUENCE FOR A TOTAL OF SIX
AFTER THE DELAY-TO-	RECYCLES. AFTER SIX UNSUCCESSFUL
	RECYCLE ATTEMPTS, THE CONTROL
FAN-OFF PERIOD ENDS,	WILL GO INTO SYSTEM LOCKOUT.
THE CIRCULATING AIR
FAN AND (OPTIONAL)
ELECTRONIC AIR CLEANER
ARE DE-ENERGIZED.

IF SYSTEM IS IN LOCKOUT, THE

MODULE WILL RESET ITSELF AFTER

60 MINUNTES OR MAY BE MANUALLY RESET BY

INTERRUPTING THE POWER TO THE

FURNACE AT THE DISCONNECT OR INTERRUPTING THE CALL FOR HEAT AT THE THERMOSTAT.

IF THIS DOES NOT RESTART THE SYSTEM,

REFER TO THE TROUBLESHOOTING

SECTION OF THIS MANUAL.

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