3.3 REFRIGERATION SYSTEM COMPONENTS
Compressor
The compressor is the "heart" of the refrigeration unit, consisting of an electrical motor and a
"pump" sealed inside a steel case. The compressor used on R134A refrigerant systems is
virtually the same in external appearance as the compressor used with R600a refrigerants.
However, due to changes in lubricants and other internal differences, the compressors are not to
be interchanged, otherwise system failure will result. If a new compressor is to be installed, pull
one of the plugs to ensure that it is properly pressurized. If no pressure is observed, do not use
the compressor. If unit is pressurized, reinstall the plug and keep the compressor sealed until it
is installed and ready for solder connections. Whenever the compressor is replaced, the sealed
system must be flushed especially for R134a system.
Condenser
The condenser is a long folded tube with steel wires which receives the hot, high pressure vapor
from the compressor. While the most common problem is keeping the condenser clean from lint
and dirt buildup which prevents proper airflow and the required transfer of the heat to the
surroundings, it is possible that due to an un-repairable leak or a non-removable restriction, the
condenser could require replacement. As with any R134A sealed system repair, the key to
success is the limiting of the time of atmospheric exposure. Do not remove the plugs on the
condenser inlet and outlet tubes until the new condenser is mounted in place and made ready for
brazing. The inlet side will connect to the hot pipe and the outlet to the filter dryer for built-in
models and for built-in models the condenser can be replaceable. But for free-standing models
the inlet side will connect to the discharge pipe of compressor and the outlet to filter dryer, it is
non-replaceable.
Evaporator
The evaporator is a fin tube type within the rear side of cabinet and can be replaceable. If a
leak is present in the evaporator, it is not repairable and must be replaced. After mounting the
evaporator in place, connect the capillary tube to the replacement filter drier. Again, whenever
the evaporator assembly is replaced on R134A units, recommended that the compressor must
also replaced and the sealed system flushed.
Filter Drier
Whenever the sealed system is entered, the filter drier must and can be replaced. For R134A
refrigerant systems, use the designated filter drier from our company. This filter drier has the
proper desiccant suitable for the refrigerant. The filter drier is stamped with an arrow which
indicates the direction of refrigerant flow. The drier inlet has two lines -one connects to the
condenser and the other will be used as a process tube through which the system sweep and
final charge will be made. The drier outlet will be connected to the capillary tube. Care should
be taken to ensure that the capillary is not inserted too far into the filter drier to make contact with
its internal screen, yet in far enough to prevent restricting the small diameter capillary tube
opening with the solder alloy.
Hot Pipe
The hot pipe is a
non-replaceable
component of the sealed system routed within the walls of the
cabinet. To diagnose the hot pipe, the tubing must be isolated from the sealed system. If the
hot pipe fails to hold the vacuum, a heater repair assembly is to be installed and the hot pipe
bypassed by connecting the condenser outlet tube directly to the inlet of filter drier.
Capillary
The capillary tube meters the flow of refrigerant and creates a pressure drop. Size and length of
the capillary is critical to the efficiency of the system.
