Thermo Products CHX3-75N, CDX3-75N, CHX3-125N IF THERMOSTAT W2 CONTACTS ARE CLOSED OTHERWISE

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

IF THERMOSTAT

W2 CONTACTS

ARE CLOSED

OTHERWISE

AFTER DELAY-TO-FAN-ON PERIOD ENDS (45 SECONDS), CIRCULATING AIR FAN IS ENERGIZED AT LOW FIRE HEATING SPEED OR HIGH FIRE IF W2 IS ENERGIZED. THE (OPTIONAL) ELECTRONIC AIR CLEANER AND HUMIDIFIER

ARE ENERGIZED.

IF SYSTEM IS IN LOCKOUT,

THE MODULE WILL RESET

ITSELF AFTER 60 MINUTES

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.

	THERMOSTAT CLOSES W2
	CALLING FOR HIGH FIRE
CALL
	HEATING.
FOR
HIGH
FIRE

NO CALL

FOR

HIGH FIRE

WHEN THERMOSTAT W1 IS SATISFIED, CONTACTS OPEN AND THE GAS VALVE IS DE-ENERGIZED. AFTER PROOF OF FLAME LOSS, INDUCER STARTS 5 SECOND POST PURGE

AND (OPTIONAL) HUMIDIFIER IS DE-ENERGIZED. THE DELAY-TO- FAN-OFF PERIOD BEGINS (120 SECONDS)

AFTER THE DELAY-TO-FAN-OFF PERIOD ENDS, THE CIRCULATING AIR FAN AND (OPTIONAL) ELECTRONIC AIR CLEANER ARE DE-ENERGIZED.

GAS VALVE, INDUCER AND AIR FAN ARE ENERGIZED TO HIGH FIRE SETTINGS

WHEN THERMOSTAT HAS SATISFIED W2, CONTACTS OPEN AND THE GAS VALVE AND AIR FAN HIGH FIRE SETTINGS ARE DE-ENERGIZED AFTER 30 SECOND DELAY.

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