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THERMOSTAT CALLS FOR COOLING
(Y1 POWERED)
COOLING CONTACTOR OF FIRST-STAGE
CONDENSING UNIT CLOSES AND SYSTEM
BLOWERS START.
YES
HAS ROOM AIR TEMPERATURE CONTINUED
TO RISE ABOVE THE THERMOSTAT"S
Y2 SET POINT?
COOLING CONTACTOR OF SECOND-STAGE
CONDENSING UNIT CLOSES.
IS Y2 DEMAND SATISFIED?
YES
SECOND-STAGE COOLING
UNIT CONTACTOR OPENS
YES
IS Y1 DEMAND SATISFIED?
FIRST-STAGE COOLING UNIT
CONTACTOR OPENS AND B3
SYSTEM BLOWERS OFF.
FOR TWO CONDENSING UNITS
FOR A SINGLE CONDENSING UNIT
THERMOSTAT CALLS FOR COOLING
(Y1 POWERED)
COOLING CONTACTOR OF CONDENSING UNIT
CLOSES AND SYSTEM BLOWERS START.
YES
IS Y1 DEMAND SATISFIED?
COOLING UNIT CONTACTOR
OPENS AND B3 SYSTEM
BLOWERS OFF.
MANUAL FAN OPERATION
THE BLOWERS RUN CONTINUOUSLY WITH OR
WITHOUT A CALL FOR HEATING OR COOLING.
MANUAL FAN SELECTION MADE AT THERMOSTAT.
COOLING SEQUENCE OF OPERATION