Whirlpool ATE0743RPP, Technical Manual

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3-1
PRODUCT OPERATION
THEORY OF OPERATION
Refrigeration Operation
The refrigeration system uses the following
four basic principles in its operation:
1. Heat always flows from a warmer body to
a cooler body.
2. Heat must be added to or removed from a
substance before a change in state can
occur.
3. Flow is always from a higher pressure
area to a lower pressure area.
4. The temperature at which a liquid or gas
changes state is dependent upon the pres-
sure.
The refrigeration cycle begins at the compres-
sor. Starting the compressor creates a low
pressure in the suction line which draws refrig-
erant gas (vapor) into the compressor. The
compressor then “compresses” this refriger-
ant, raising its pressure, and its temperature.
The refrigerant leaves the compressor through
the discharge line as a hot, high pressure gas.
The refrigerant enters the condenser coil where
it gives up some of its heat. The condenser fan
moves air across the finned surface of the
condenser coil, and facilitates the transfer of
heat from the refrigerant to the relatively cooler
outdoor air.
When a sufficient quantity of heat has been
removed from the refrigerant gas, the refriger-
ant will “condense” (change to a liquid). Once
the refrigerant has been condensed to a liquid,
it is further cooled by the air flowing across the
condenser coil.
The Packaged Terminal Air Conditioner (PTAC)
design determines at exactly what point (in the
condenser) the change of state (gas to liquid)
takes place. In all cases, however, the refriger-
ant must be totally evaporated (changed to a
gas) before leaving the evaporator coil.
Discharge Line
Suction Line
Evaporator Coil
Condenser Coil
Liquid Line
Capillary Tube
(Metering)
Refrigerant
Strainer
Filter/Drier
Compressor