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Refrigeration Sequence of Operation
A good understanding of the basic operation
of the refrigeration system is essential for the
service technician. Without this understanding,
accurate troubleshooting of refrigeration
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time consuming, if not (in some cases) entirely
impossible. The refrigeration system uses four
basic principles (laws) in its operation:
1.
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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
pressure."
The refrigeration cycle begins at the compressor.
Starting the compressor creates a low pressure
in the suction line which draws refrigerant gas
(vapor) into the compressor. The compressor
then "compresses" this refrigerant, raising its
pressure and its (heat intensity) temperature.
The refrigerant leaves the compressor through
the discharge line as a hot high pressure gas
(vapor). The refrigerant enters the condenser coil
where it gives up some of its heat. The condenser
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facilitates the transfer of heat from the refrigerant
to the relatively cooler outdoor air.
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removed from the refrigerant gas (vapor), the
refrigerant will "condense" (i.e.: change to a
liquid). Once the refrigerant has been condensed
(changed) to a liquid it is cooled even further
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condenser coil.
The GE Vertical Zoneline design determines at
exactly what point (in the condenser) the change
of state (i.e.: gas to a liquid) takes place. In all
cases, however, the refrigerant must be totally
condensed (changed) to a liquid before leaving
the condenser coil.
The refrigerant leaves the condenser coil through
the liquid line as a warm high pressure liquid. It
next will pass through the refrigerant drier (if so
equipped). It is the function of the drier to trap any
moisture present in the system, contaminants,
and large particulate matter.
The liquid refrigerant next enters the metering
device. The metering device is a capillary
tube. The purpose of the metering device is to
"meter" (i.e.: control or measure) the quantity of
refrigerant entering the evaporator coil.
In the case of the capillary tube, this is
accomplished (by design) through size (and
length) of device, and the pressure difference
present across the device.
Since the evaporator coil is under a lower
pressure (due to the suction created by the
compressor) than the liquid line, the liquid
refrigerant leaves the metering device entering
the evaporator coil. As it enters the evaporator
coil, the larger area and lower pressure allows
the refrigerant to expand and lower pressure
allows the refrigerant to expand and lower its
temperature (heat intensity). This expansion
is often referred to as "boiling". Since the GE
Vertical Zonelines blower is moving indoor air
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the expanding refrigerant absorbs some of that
heat. This results in a lowering of the indoor air
temperature, hence the "cooling" effect.
The expansion and absorbing of heat cause the
liquid refrigerant to evaporate (i.e.: change to a
gas). Once the refrigerant has been evaporated
(changed to a gas), it is heated even further
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evaporator coil.
Summary of Contents for GE Vertical Zoneline AZ90E09D C
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