Lennox International Inc G50UH-24A-045, G50UH-48C-110 I--=- l, YES t, Hascontrolreset,Gn,T,On

NORMAL HEATING MODE ABNORMAL HEATING MODE

15-SECOND COMBUSTION AIR INDUCER PREPURGE N T ATED BY CLOSED PRESSURE SW TCH.

YES _

IIGNITOR WARM-UP -- 20 SECONDS. YES

GAS VALVE OPENS, IGNITOR ENERGIZED FOR

I4-SECONDUP TOTRIAL4SECONDS,FORIGNITION.

9
-_O	S VOLTAGE ABOVE 75 VOLTS?	. NO I LEDS SIGNAL
	YES_
		ALTERNATING
_IIW	YES_t	INO FAST FLASH
	ISTHERE A PROPER GROUND?	I--=-_l

ISIGNITOR INTACT AND CONNECTED?I_"I

YES

IFLAME STABILIZATION PERIOD.

4 SECONDS

FLAME RECTIFICATION CURRENT

CHECK. CAN FLAME BE PROVEN WITHIN 4 SECONDS AFTER GAS VALVE OPENS?

( > 0.24 microamps)

YES _

FLAME PRESENT?

YES _

IFLAME SIGNAL ABOVE 0.31 MICROAMPS? YES _

IINDOOR BLOWER ON DELAY BEGINS

(45 seconds,)

YES _1

PRIMARYSWITCHESANDSECONDARYCLOSED? LIMIT

I

I

I_

I

-

I

F-

		INDOOR		BLOWER		OFF.	FOR	I	NO
	HAS CONTROL		FA LED TO SENSE FLAME
	FIVE CONSECUTIVE TRIES DURING A SINGLE
		HEAT DEMAND?
					t
	COMBUSTION			AIR INDUCER OFF.
	GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
	INDOOR BLOWER				OFF WITH DELAY				YES
	IGNITION	WATCHGUARD			MODE. GAS VALVE OFF. I
	LED 1 ALT. SLOW		FLASH		LED 2 ALT SLOW		FLASH	I	I
	IS 60-MINUTE		RESET		PERIOD COMPLETE?			I,.__	I
								_,Z_.I_
	HASCONTROLRESET,GN,T,ON								NO
I		SEQUENCE			FOUR	TIMES?		/	Ii
	LOW FLAME SIGNAL						YESl
	LED #1 -- SLOW			FLASH
I	(Does not affect operation of control)
	LED #2 -- FAST FLASH						LIMIT SWITCH WATCH-
							GUARD MODE. GAS
	GAS VALVE DE-ENERGIZED						VALVE OFF. COMB. AIR
	COMBUSTION		AIR INDUCER				INDUCER OFF. INDOOR
	DE-ENERGIZED.INDOOR				BLOWER		BLOWER		OFF WITH
ON UNTIL		SWITCH	CLOSES.LED			#1	DELAY, LED#I-SLOW
	-- SLOW FLASH, LED #2 -- ON.						FLASH LED#2 - ON. IS

YES

IROLLOUT SWITCH CLOSED?

q

YES _

÷1 COMBUSTION AIR PRESSURE SWITCH CLOSED?

YES _

I	THERMOSTAT DEMAND	SATISFIED.	I
	YES
I	LED #1 & #2 SIMULTANEOUS	SLOW FLASHES.	I

YES _

COMB. AIR INDUCER CONTINUES 5-SECOND POST PURGE AFTER T'STATDEMAND IS SATISFIED, INDOOR AIR BLOWER COMPLETES SELECTED "OFF"

DELAY BEFORE SHUTTING OFF.

	IS LIMIT SWITCH CLOSED?		60MINUTE RESET
			PERIOD COMPLETE?
	YES
	HAS PRIMARY/SECONDARY		LIMIT
	RESET (CLOSED)	WITHIN	3
	MINUTES?		YES
NO	GAS VALVE		POWER OFR
	COMBUSTION AIR INDUCER POWER OFF.
	INDOOR BLOWER OFF WITH DELAY
	LED #1 --	ON. LED #2 -- SLOW FLASH,

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS RESET

YES

	COMBUSTION	AIR INDUCER	ON.	YES
	INDOOR BLOWER OFF WITH DELAY
I	LED #1 -- OFF. LED #2 -- SLOW FLASH,
	GAS VALVE DE-ENERGIZED		MINUTES?
	HAS CAB SWITCH	CLOSED IN 2.5

NO_

I 5-MINUTEWATCHGUARDPRESSUREMODE,SWITCH ]

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