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5.7 Safety functions
For protection against low-pressure, the low-pressure switch is added (RDP 750-1900). Other safety
functions are implemented in the controller.
5.7.1 Low-pressure switch
LPS: Low-pressure protection device on the suction side of the compressor trips, if the pressure drops
below the pre-set value. The values are automatically reset when the nominal conditions are restored.
Calibrated pressure: R 134.a Stop 0.7 barg - Restart 1.7 barg
5.7.1 Safety functions of RDC 2
CAUSE - PROPOSED ACTIVITY
Temperature sensor failure - Ensure that the temperature sensor is properly
connected to the controller / replace the temperature switch
1 – Dew point sensor
2 – Compressor sensor
3 – Condensation sensor
High condensation temperature/pressure – Check that the temperature sensor
is correctly inserted into its position, check the cooling system sealing / charging
/ check the hot gas bypass valve
Low dew point temperature - Check that the temperature sensor is correctly
inserted into its position, check the cooling system sealing / charging / check the
hot gas bypass valve
High compressor outlet temperature – Check that the temperature sensor is
correctly inserted into its position, check the cooling system sealing / charging /
check the hot gas bypass valve
5.8 Filter / dehydrator
Moisture and impurities can be present in the refrigeration circuit. This can reduce the lubrication of
the compressor and block the expansion valve or capillary tube. The dryer filter / dehydrator is located
in front of the capillary tube to remove moisture and impurities from the circulation system.
5.9 Capillary tube
The capillary tube is located between the condenser and the evaporator and functions as a metering
device for reducing the pressure of the refrigerant. The pressure reduction is a design-based function.
The length and inner diameter of the capillary tube are precisely dimensioned, ensuring good
performance in all designed conditions.
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