Lennox G60UHV Series Installation Instructions Manual page 47

CONTINUED
HEATING SEQUENCE OF OPERATION
SEE BOX A
NORMAL OPERATION.
SEE BOX B
THERMOSTAT CALLS FOR HEAT.
I SECOND-STAGE (HIGH FIRE) HEAT
PRESSURE SWITCH CLOSED?
YES _
I HEAT DEMAND SATISFIED?
STATUS LED -- HEARTBEAT.
YES YES 1
[ SINGLE-STAGE THERMOSTAT MODE 1 I '
(DiP SWITCH SET AT "SINGLE")
I I
I
L 1 I.
YES I
GAS VALVE OFF, COMBUSTION AIR
INDUCER OFF AFTER 5-SECOND
LOW SPEED POST PURGE PERIOD,
INDOOR BLOWER OFF DELAY
INITIATED ON LOW HEAT SPEED,
STATUS LED - HEARTBEAT.
DEMAND FOR HEAT SATISFIED.
POWER ON STAND BY.
STATUS LED -- PULSE.
I
I
NO
I
RETURN TO FIRST-STAGE HEAT MODE.
FIRST-STAGE CONTINUES UNTIL SECOND-
STAGE PRESSURE SWITCH CAN BE PROVEN
or HEAT DEMAND IS SATISFIED. A FIVE (5)
MINUTE WAIT PERIOD IS INITIATED BEFORE
RETRY. WERE 5 ATTEMPTS MADE FOR
SECOND-STaGE HEAT?
NO
,_
SEE BOX C
FIRST-STAGE HEAT DEMAND SATISFIED?
I
TWO STAGE THERMOSTAT MODE? 3,
(DIP SWITCH SET AT "TWO") I
J
YES'f
._ SECOND STAGE HEAT
FIRST AND SECOND STAGE HEAT DEMAND SASTISFIED?
DEMAND SATISFIED SIMULTANEOUSLY. STATUS LED -- HEARTBEAT.
STATUS LED -- HEARTBEAT.
YES _
I GAS VALVE, COMBUSTION AIR INDUCER
AND INDOOR BLOWER RETURN TO FIRST-
STAGE OPERATION.
STATUS LED -- HEARTBEAT.
I FIRST STAGE HEAT DEMAND SATISFIED? I
YES
4 GAS VALVE OFF. COMBUSTION AIR INDUCER
OFF AFTER 5-SECOND LOW SPEED POST-
PURGE PERIOD. INDOOR BLOWER OFF.
DELAY INITIATED ON LOW HEAT SPEED,
STATUS LED -- PULSE,
Page 47