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Operation Manual
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10.9.2
Low Pressure Ratio
This alarm indicates that the ratio between evaporating and condensing pressure is below a limit which depends on
compressor speed and guarantees the proper lubrication to compressor.
Symptom
Cause
Solution
Circuit status is Off.
The circuit is stopped.
Bell icon is moving on controller’s
display. String in the alarm list:
CxCmp1 OffPrRatioLo
String in the alarm log:
CxCmp1 OffPrRatioLo
String in the alarm snapshot
CxCmp1 OffPrRatioLo
Compressor is not able to develop the
minimum compression.
Check fan setpoint and settings, it
could be too low (Condenserless
units).
Check compressor absorbed current
and discharge superheat.
Compressor can be damaged.
Check the correct operation of suction
/ delivery pressure sensors.
Check the internal relief valve didn’t
opened during previous operation
(check the unit history).
Note:
If the difference between delivery and
suction pressure exceed 22bar, the
internal relief valve open and need to
be replaced.
Inspect the gate rotors / screw rotor
for possible damages.
Check if the cooling tower or three
way valves are operating correctly
and properly set.
Reset
Notes
Local HMI
Network
Auto
10.9.3
Oil Pressure Sensor Fault
This alarm is generated to indicate that the sensor is not reading properly.
Symptom
Cause
Solution
Circuit status is Off.
The circuit is switched off with the
normal shutdown procedure.
Bell icon is moving on controller’s
display.
String in the alarm list:
CxCmp1 OffOilFeedPSen
String in the alarm log:
CxCmp1 OffOilFeedPSen
String in the alarm snapshot
CxCmp1 OffOilFeedPSen
Sensor is broken.
Check for sensor integrity.
Check correct sensors operation
according information about mVolt
(mV) range related to pressure values
in kPa.
Sensor is shorted.
Check if sensor is shorted with a
resistance measurement.
Sensor is not properly connected
(open).
Check for correct installation of the
sensor on refrigerant circuit pipe. The
transducer must be able to sense the
pressure through the valve’s needle.
Check for absence of water or
humidity on sensor electrical contacts.
Check for correct plug-in of the
electrical connectors.
Check for correct sensors wiring also
according electrical scheme.
Reset
Notes
Local HMI
Network
Auto
