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Air and Water cooled inverter chillers and heat pump
EWAD TZ - EWAD TZ B - EWWD VZ
Air and Water cooled inverter chillers
and heat pump
D-EOMZC00105-17EN
Operation Manual
79/84
Reset
Notes
Local HMI
Network
Auto
6.6.21 Mechanical High Pressure Alarm
This alarm is generated when the condenser pressure rises above the mechanical high pressure limit causing
this device to open the power supply to all the auxiliary relays. This causes an immediate shutdown of
compressor and all the other actuators in this circuit.
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.
String in the alarm list:
CxCmp1 OffMechPressHi
String in the alarm log:
CxCmp1 OffMechPressHi
String in the alarm snapshot
CxCmp1 OffMechPressHi
One or more condenser fans do not
operate properly(A/C units).
Check if fans protections have been
activated.
Check that the fans can turn freely.
Check that there is not any obstacle to the
free ejection of the air blown.
Condenser pump may not be operating
correctly (W/C units)
Check if the pump can run and give the
required water flow.
Dirty or partially blocked condenser coil
(A/C units).
Remove any obstacle;
Clean the condenser coil using soft brush
and blower.
Dirty condenser heat exchanger (W/C
units)
Clean the condenser heat exchanger.
Inlet air temperature of the condenser is
too high (A/C units).
The air temperature measured at the inlet
of the condenser may not exceed the limit
indicated in the operational range (working
envelope) of the chiller (A/C units).
Check the location where the unit is
installed and check that there are no any
short circuit of the hot-air blown from the
fans of the same unit, or even from fans of
next chillers (Check IOM for proper
installation).
One or more condenser
fan turning in wrong
direction.
Check for correct phases sequence (L1,
L2, L3) in the electrical connection of the
fans.
Entering water temperature at condenser
is too high (W/C units).
Check the cooling tower operation and
settings.
Check the three way valve operation and
settings.
Mechanical high pressure switch is
damaged or not calibrated.
Check for proper operation of the high
pressure switch.
Reset
Notes
Local HMI
Network
Auto
Reset of this alarm requires a manual
action on the high pressure switch.
6.6.22 Mechanical Low Pressure Alarm (W/C units only)
This alarm is generated when the evaporating pressure drops below the mechanical low pressure limit causing
this device to open. This causes an immediate shutdown of compressor to prevent from freezing.
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.
String in the alarm list:
CxCmp1 OffMechPressLo
String in the alarm log:
CxCmp1 OffMechPressLo
String in the alarm snapshot
CxCmp1 OffMechPressLo
Refrigerant charge is low.
Check sight glass on liquid line to see if
there is flash gas.
Measure sub-cooling to see if the charge
is correct.
High Evaporator Approach.
Clean the evaporator
Check the quality of the fluid that flows into
heat exchanger.
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.