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Air and Water cooled inverter chillers and heat pump
D-EOMZC00105-17EN
Operation Manual
78/84
EWAD TZ - EWAD TZ B -EWWD VZ
Air and Water cooled inverter chillers and
heat pump
Check the glycol percentage and type
(ethilenic or propilenic)
Water flow into water heat exchanger is too
low.
Increase the water flow.
Check that evaporator water pump is
operating correctly providing the required
water flow.
Evaporating pressure transducer is not
working properly.
Check the sensor for proper operation and
calibrate the readings with a gauge.
EEXV is not working correctly.
It’s not opening enough or it’s moving in
the opposite direction.
Check if pump-down can be finished for
pressure limit reached;
Check expansion valve movements.
Check connection to the valve driver on the
wiring diagram.
Measure the resistance of each winding, it
has to be different from 0 Ohm.
Water temperature is low
Increase inlet water temperature.
Check the low pressure safeties settings.
Reset
A/C units
W/C units
Notes
Local HMI
Network
Auto
6.6.19 Low Pressure Ratio Alarm
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 (A/C 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
6.6.20 Maximum Number of Restart Alarm (A/C units only)
This alarm indicates that for three consecutive times after the compressor start the evaporating pressure is
under a minimum limit for too much time
Symptom
Cause
Solution
Circuit status is Off.
The circuit is stopped.
Bell icon is moving on controller’s display.
String in the alarm list:
Cx OffNbrRestarts
String in the alarm log:
Cx OffNbrRestarts
String in the alarm snapshot
Cx OffNbrRestarts
Ambient temperature is too low
Check the operating envelope for this
machine.