SRC Service Manual
Revision 02
Aug 2007
3.3.3 Refrigerant
Filter
The refrigerant filter is of a solid desiccant type construction that removes
solid and liquid contaminants from the refrigerant. Without it,
contaminants would re-circulate throughout the circuit continuously. Solid
contaminants could damage the compressor or block the flow of
refrigerant. Moisture could cause the compressor oil to become acidic.
The filter/dryer catches any solid contaminants in the system and absorbs
any moisture.
It is important to replace the filter if it becomes blocked, if the refrigerant system has been open to
atmosphere for an extended period of time, or if the compressor has been replaced.
3.3.4 Expansion
Device
The expansion device reduces the pressure (and therefore
temperature) of the refrigerant and regulates it’s flow into the
Coolant-to-Refrigerant Heat Exchanger.
The SRC-150 to 500 use a capillary tube expansion device. The
capillary tube is a copper tube of precise length and diameter
that provides a specific pressure drop and choked flow rate.
The SRC-700 to 1000 use a thermostatic expansion valve. The
valve adjusts the flow of refrigerant entering the evaporator to
maintain a specific superheating. When the superheating
increases, the valve opens to allow more refrigerant to enter the
heat exchanger. When the superheating decreases, the valve closes to reduce the amount of
refrigerant getting into the heat exchanger.
SR-150 to 500 SRC-700 to 1000
3.3.5 Refrigerant
The refrigerant is the medium used to transfer energy. By changing pressure and temperature and
changing from a liquid to a gaseous state it effectively transforms the input energy (i.e. compressor
electrical energy) to output energy (i.e. chilling of the coolant). All SRC models feature R407C
refrigerant. R407C is classified as an environmentally friendly refrigerant, and offers an O.D.P. (Ozone
Depletion Potential) of zero; as a consequence R407C has no planned phase-out date and can be
used without restrictions. It also offers a very low G.W.P. (Global Warming Potential) level. R407C
furthermore features a high C.O.P. (Coefficient of Performance), thereby ensuring that the dryer’s
power consumption is kept to a minimum.
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