LG Electronics 395CAV installation instructions ÐControl Board, Ð9Ð

	BLOWER OFF DELAY
	ADJUSTMENT SWITCH
	G	24V THERMOSTAT
		TERMINALS
	R
	Y
TEST/TWIN	W	HUMIDIFIER TERMINAL
	Com
	24V	(24-VAC 0.5 AMP MAX)
	HUM	LED OPERATION &
		DIAGNOSTIC LIGHT
		HARNESS CONNECTOR

SEC-1	24V TRANSFORMER SEC-2
3-AMP FUSE	SPARE 1
COOL
	BLOWER SPEED
HEAT
	SELECTION TERMINALS
	SPARE 2
	EAC 1 (BLACK)
	EAC-ELECTRONIC AIR CLEANER
	TERMINALS (115-VAC 1.5 AMP MAX)
115-VAC (L1)	EAC 2 (WHITE)
POWER	115-VAC (L2) NEUTRAL
SUPPLY
	CONNECTION
HOT SURFACE	INDUCER MOTOR
IGNITOR	CONNECTOR
CONNECTOR

A93052

Fig. 9ÐControl Board

A93053

Fig. 10ÐEAC Terminals on Control Board 1. Heating mode

When the wall thermostat "calls for heat," the R-W circuit closes. The furnace control performs a self-check, verifies the pressure switch contacts are open, and starts inducer motor.

a. Prepurge periodÐAs the inducer motor comes up to speed, the pressure switch contacts close to begin a 15-sec prepurge period.

b. Ignitor warm-upÐAt the end of the prepurge period, the ignitor is energized for a 17-sec ignitor warm-up period.

c. Ignition sequenceÐWhen the ignitor warm-up period is completed, the gas valve opens, permitting gas flow to the burners where it is ignited. After 5 sec, the ignitor is de-energized and a 2-sec flame-sensing period begins.

Ð9Ð

d. HUM terminal is energized with the gas valve. See accessories in the Electrical Connections section.

e.Flame-sensingÐWhen burner flame is sensed, the con- trol begins the blower on delay period and continues holding the gas valve open. If burner flame is not sensed, the control closes the gas valve and repeats ignition cycle.

NOTE: Ignition sequence will repeat 3 additional time before a lockout occurs. Lockout automatically resets after 3 hrs, or can be manually reset by turning 115v off (not at thermostat) for 3 sec minimum, then on again.

f.Blower on delayÐForty sec after burner flame is proven, the blower motor is energized on heating speed. Simul- taneously, the humidifier and electronic air cleaner terminals (HUM and Com for humidifier, EAC-1 and EAC-2 for electronic air cleaner) are energized. If jumper is on pin 6 and pin 9, blower on delay is 60 sec.

g.Blower off delayÐWhen the thermostat is satisfied, the circuit between R-W is broken, de-energizing the gas valve stopping gas flow to the burners. The blower motor and EAC remain energized 90, 135, 180, or 225 sec (depending on the blower off-time selection). The furnace is factory set for a 135-sec blower off delay.

h.Post-purgeÐThe inducer motor remains energized 5 sec after the burners are extinguished. If jumper is on pin 6 and pin 9, the post-purge period is 15 sec.

2.Cooling mode

When the thermostat "calls for cooling," R-G and R-Y circuits close. The R-Y circuit starts the outdoor condensing