10.8.4 Mechanical High Pressure Switch
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.
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 (Condenserless
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.
Check if the pump can run and give
the required water flow.
Dirty or partially blocked condenser
coil (Condenserless units).
Remove any obstacle;
Clean the condenser coil using soft
brush and blower.
Dirty condenser heat exchanger.
Clean the condenser heat exchanger.
Inlet air temperature of the condenser
is too high (Condenserless 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
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.
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 of this alarm requires a manual
action on the high pressure switch.
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