SRC Service Manual
Revision 02
Aug 2007
3.2.5 Coolant Pressure Relief Valve
The Coolant Pressure Relief Valve protects the Coolant Circuit from over-
pressure. It is set at 87 psig (6 barg).
3.2.6 Coolant Expansion Tank
The Coolant Expansion Tank allows the Coolant to expand and contract as it
increases and decreases in temperature.
3.3 Refrigeration
Circuit
All models operate on a thermal mass principal, which cycles the refrigeration circuit on and off
according to the system load. For details of cycling operation, refer to Section 8.
The main components of the refrigeration circuit are the Compressor, the Condenser, the
Refrigerant Filter, the Expansion Device, and the Coolant-to-Refrigerant Heat Exchanger (Evaporator)
(as described in 3.2.2 above). In addition, there are several control components:
•
High Pressure Switch
- to shut down the dryer in the event of overpressure of the refrigerant system,
•
Low Pressure Switch (SRC-250 to 1000)
– to prevent freezing in the event of a system upset, and
•
Fan Pressure Switch
– to cycle the condenser fan on and off.
These components are connected in a closed loop with pipes made entirely from high quality copper,
through which the refrigerant flows. All models use R407C refrigerant.
The refrigeration circuit functions as a closed loop.
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