304 C – 02/06 D – pag. 7/16
Freeze protection
If the unit is installed in an area where the ambient temperature can fall below 0°C, the heat exchanger, the piping
and the inertial water tank can be damage by frost, despite the electric heater (standard supplied on the heat
excharger and the tank). In this case is recommended to add ethylene glycol with an adeguate concentration (see
table on page 3) to protect the installation down to a temperature of 10 K below the lowest temperature likely to
occur at the installation site (for example if the minimum forecast temperature is –13°C, must be considered a
temperature of –23°C). If the unit is switched off and if the above-mentioned precautions are not followed, it is
recommended to drain the hydraulic circuit.
Damage due to freezing is not covered by the warranty.
Microprocessor ALZ 011.1 ÷ 020.1
Compact µchiller is a versatile electronic controller as compact as a standard thermostat, specifically designed for
the control of heat pumps.
Main functions
•
Control of water temperature at evaporator inlet (inlet air)
•
Time-based and/or temperature-based defrosting cycles
•
Control of fan speed
•
Full alarm management
•
Can be linked up to serial line for supervisory telemaintenance control
•
Can be linked up to an external terminal unit
Controlled devices
•
Compressor
•
Condensation fans
•
Water pump or supply fan (air-to-air)
•
Antifreeze heaters
•
Alarm signalling device
User interface
Display -
The display consists of 3 digits, with the automatic display of the decimal point between -19.9 and +
19.9°C; outside this measurement range, the value is automatically displayed without decimal (although in its
inside the machine is always operating by taking into account the decimal part). During the normal operation, the
displayed value corresponds to the temperature being read by the probe B1, that is the evaporator water inlet
temperature.
Status of the unit -
The User is informed of the status of the unit by means of four LEDs on the display.
Meaning of LEDs in single-compressor units
LED
Flashing
Steady
Compressor
Request for compressor
Compressor actuated
Cooling
-
Cooling
Heating
-
-
Χ
100
-
Visualized value x100
Parameters setting (see page 13)
Alarms and signalling
Any time an alarm condition is detected, the controller will prompt the following actions:
•
the buzzer sounds
•
the alarm relay energizes
•
the temperature value blinks on display
•
the alarm code appears on the LCD alternatively with the temperature value
