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
77
Check the phase cut device.
6.1.7.3 High Pressure alarm
This alarm is generated if the condensing pressure rise above the Hi Press Stop limit.
Symptom
Cause
Solution
Circuit status is Off.
The compressor does not load
anymore
or
even
unload,
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 CndPressHi
String in the alarm log:
Cx Off CndPressHi
String in the alarm snapshot:
Cx Off CndPress Hi
The condenser pump does
not operate properly. (W/C
only)
Check if condenser pump protections have been
activated.
Condenser water flow too
low (W/C or H/P only)
Check the minimum water flow admitted
Inlet water temperature of
the condenser is too high.
(W/C only)
The water temperature measured at the inlet of the
condenser may not exceed the limit indicated in the
operational range (working envelope) of the chiller.
Excessive charge of
refrigerant into the unit.
Check liquid sub-cooling and suction super-heat to
control indirectly the correct charge of refrigerant.
If necessary recover all the refrigerant to weight the
entire charge and to control if the value is in line with kg
indication on unit label.
Condensing
pressure
transducer
could
not
operate properly.
Check for proper operation of the high pressure sensor.
Fans
do
not
operate
properly (A/C only)
Check Fans operation. Check that all the fans can run
freely and at the proper speed.
Check the phase cut device.
6.1.7.4 Low Delta Pressure Alarm (A/C only)
This alarm is generated if the pressure difference between condensing and evaporating pressure is
below a minimum Delta Pressure limit for more than 10 minutes.
Symptom
Cause
Solution
Circuit status is Off.
The compressor does not load
anymore or even unload, 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 DeltaPressLo
String in the alarm log:
CxOff DeltaPressLo
String in the alarm snapshot:
CxOff CxOff DeltaPressLo
Compressors are not running
Check
the
starter
signals
to
compressors.
Check if the Thermal protection of
compressors is properly connected to
the UC (see section 6.1.7.5).
Check
if
the
Mechanical
High
Pressure
Switch
is
properly
connected to the UC (see section
6.1.7.5).
Condenser Pressure Transducer is
not working properly
Refer to section 6.1.7.10 for further
details.
Evaporator Pressure Transducer is
not working properly
Refer to section 6.1.7.9 for further
details.
6.1.7.5 Circuit X Alarm
This alarm is generated when the digital input DI1 on the EXV driver of the related circuit is open.
This digital input collects a series of alarm signals coming from different protection devices:
1. Mechanical High Pressure Switch
2. Compressor 1 Circuit X Thermal Protection/Soft Starter Failure
3. Compressor 2 Circuit X Thermal Protection/Soft Starter Failure
4. Phase cut device failure (A/C only)
