EWWQ090G ÷ EWWQ720L - R410A - Water-cooled scroll chillers
EWLQ090G ÷ EWLQ720L - R410A - Condenser less
EWHQ100G ÷ EWHQ400G - R410A - Heat pump scroll chillers
EWAQ-
- R410A - Air-cooled scroll chillers
EWAQ-
- R410A - Air-cooled scroll chillers
EWYQ-
- R410A - Air-cooled scroll heat pumps
Air and Water cooled scroll chillers & heat pump
Operation
Manual
EWWQ - EWLQ - EWHQ
EWAQ - EWYQ
Air or Water cooled scroll chiller &
heat pump
D-EOMHW00107-15EN
Operation Manual
79
6.1.7.7 Restart Fault Alarm
This alarm can occurs only if the condenser less unit type is configured. This alarm is generated if
for three times the UC recognizes a low evaporating pressure and a low saturated condensing
temperature at the starting of the circuit.
Symptom
Cause
Solution
Circuit status is Off.
The circuit is stopped.
Bell icon is moving on controller’s
display.
Led on the button 2 of External HMI is
blinking
String in the alarm list:
+Cx Off RestrtsFaultAlm
String in the alarm log:
Cx Off RestrtsFaultAlm
String in the alarm snapshot:
Cx Off RestrtsFault Alm
Low outside ambient temperature
Check the operating condition of the
condenser-less unit
Refrigerant charge low.
Check sight glass on liquid line to see
if there is flash gas.
Measure sub-cooling to see if the
refrigerant charge is correct.
Condensing Setpoint not correct for
the application (W/C only)
Check if necessary to increase the
condensing saturated temperature
setpoint
Dry cooler not correctly installed (W/C
only)
Check that the dry cooler is safe from
strong wind
Evaporator or condensing sensor
pressure broken or not correctly
installed
Check the proper operation of the
pressure transducers.
6.1.7.8 No Pressure Change At Start alarm
This alarm indicates that the compressor is not able to start or it is not able to create a minimum
variation of the evaporating or condensing pressures after start.
Symptom
Cause
Solution
Circuit status is Off.
The circuit is stopped.
Bell icon is moving on controller’s
display.
Led on the button 2 of External HMI is
blinking
String in the alarm list:
+Cx Off NoPressChgStartAlm
String in the alarm log:
Cx Off NoPressChgStartAlm
String in the alarm snapshot:
Cx Off NoPressChgStart Alm
Compressor cannot start
Check if the start signal is properly
connected to the compressor.
Compressor is turning in wrong
direction.
Check correct phases sequence to
the compressor (L1, L2, L3) according
to the electrical scheme.
Refrigerant
circuit
is
empty
of
refrigerant.
Check circuit pressure and presence
of refrigerant.
Not proper operation of evaporating
or condensing pressure transducers.
Check
proper
operation
of
evaporating or condensing pressure
transducers.
6.1.7.9 Evaporating Pressure sensor fault
This alarm indicates that the evaporating pressure transducer is not operating properly.
Symptom
Cause
Solution
Circuit status is Off.
The circuit is stopped.
Bell icon is moving on controller’s
display.
Led on the button 2 of External HMI is
blinking
String in the alarm list:
+CxOff EvapPressSen
String in the alarm log:
CxOff EvapPressSen
String in the alarm snapshot:
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.
