We reserve the right to make changes without prior notice
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between the measured enthalpy values is greater than the activation differential. Free cooling is active
as long as the ambient enthalpy value equals the external enthalpy value, increased (first case) and
reduced (second case) by the differential for enthalpy free cooling.
6.7.6 Hot water anti-freeze function in coil
The software manages the hot water coil during the heating cycle and in cases when special conditions may
cause the water contained in the coil to freeze.
The anti-freeze function to prevent water in the coil from freezing is enabled when the unit is not running and
the air temperature in the delivery line is close to 0°C. If this condition occurs, the controller opens the 3-way
valve according to the value set in the controller and it simultaneously enables the digital output of the water
circulation pump (outside the unit).
This function remains active until the air temperature in the delivery line reaches the threshold that activates
the anti-freeze function and the corresponding differential.
The anti-freeze function can also be activated by an external command which causes opening of the digital
input ID1 both with the unit ON and OFF (keyboard-controlled operation). In this case too, the hot water valve
is opened and the digital output of the water circulation pump (outside the unit) is enabled.
If a digital input has set the unit to OFF mode, the anti-freeze function cannot be enabled by digital input.
6.7.7 Management of heater in condensate tray
The software manages activation of a digital output that controls the heater fitted in the condensate tray in
order to prevent freezing of the water that stagnates in the tray and in its drain.
This digital output is enabled as soon as the external air temperature drops below the threshold setpoint in the
controller; it is disabled when the external air temperature rises above the threshold setpoint in the controller
plus the corresponding differential.
6.7.8 Maintenance
The controller features functions that are specifically designed for machine maintenance, such as the unit and
compressor hour meters and the option to calibrate the probe reading parameters in the unit and to test the
digital outputs in the controller. For a detailed description of these functions refer to the specific section in the
Maintenance menu.
6.7.9 Maintenance alarms
The controller records the hours of operation of the unit and of each compressor. If the hours of operation
exceed the threshold recorded in the Maintenance menu, a maintenance alarm is generated by the controller.
This alarm does not cause the unit to stop, but warns about the need for scheduled maintenance, as specified
in the Instruction Manual for Installation, Use and Maintenance.
6.7.10 Alarm history
All the triggered alarms are stored in the alarm history. For a detailed description of these functions refer to
the specific section in the Alarm History menu.
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