EVCO S.p.A.
c-pro 3 micro CHIL | Application manual ver. 1.0 | Codice 144CP3CHE104
page 73 of 120
8.16 Temperature Alarm Control
8.16.1 Low and high temperature alarm management
According to operating mode, a check is carried out on the exchanger inlet temperature, triggering an alarm where appropriate.
• In winter operation (heat pump), if the temperature falls below a given threshold for a settable lapse of time, a “low
temperature” alarm is generated: AL01.
• In summer operation (chiller), if the inlet temperature exceeds a given threshold for a settable lapse of time, a “high
temperature” alarm is generated: AL02
Via a configuration parameter, alarms can be set to be display-only alarms, or to stop the machine.
It is also possible to set a temperature-alarm inhibition delay from system start-up, so as to give the machine a chance to reach full
power.
• PA05 = High-temperature alarm set point
• PA06 = Low-temperature alarm set point
• PA07 = Temperature alarm enable delay
• PA08 = Temperature alarm management mode (display-only / machine stop)
• PA09 = Temperature alarm differential
• PA10 = System start-up alarm inhibition time.
These alarms are only detected when the machine is switched ON.
8.16.2 Management of primary exchanger efficiency alarm
If this alarm AL03 (and AL13 for Circuit # 2) is enabled (PA25 = 1), a check is made as to whether the difference between entering
and leaving chilled water temperatures at the primary exchanger, is below a Primary exchanger difference minimum threshold PA26 for
a By-pass time for primary exchanger efficiency alarm PA27.
This alarm is not managed during defrosting, if sensors are in alarm status and this alarm is a manual-reset alarm.
This alarm is only detected when the machine is switched ON.
8.17 Pressure Alarm Control
8.17.1 Management of high-pressure pressure-switch alarm
Via a digital input connected to an external pressure switch, it is possible to monitor an excess of maximum condensing pressure. The
high-pressure alarmAL11 (and AL12 for Circuit # 2) causes the immediate stopping of the refrigerating circuit, also shutting down any
compressors which may be ON, and inhibiting the start-up of others.
This alarm is only detected when the machine is switched ON.
This is a manual-reset alarm.
8.17.2 Management of high-pressure transducer alarm
If condensing pressure exceeds a given threshold, a high-pressure alarm AL31 (and AL32 for Circuit # 2) is generated. The alarm
causes the immediate stopping of the refrigerating circuit, also shutting down any compressors which may be ON, and inhibiting the
start-up of others.
This alarm is only detected when the machine is switched ON.
This is a manual-reset alarm and it can be reset if in the meantime pressure has fallen below the maximum threshold of a given
differential value.
• PA21 = High-pressure alarm set point
• PA22 = High-pressure alarm differential.
8.17.3 Management of low-pressure pressure-switch alarm (chiller mode)
Via a digital input connected to an external pressure switch, it is possible to monitor the presence of a minimum intake pressure in the
refrigerating circuit. The low-pressure alarmAL41 (and AL42 for Circuit # 2) causes the immediate stopping of the refrigerating circuit,
also shutting down any compressors which may be ON, and inhibiting the start-up of others.
At start-up of the first compressor, the alarm is delayed for a given interval, to enable the compressors to take the refrigerating circuit
to full pressure.
The alarm is initially auto-resetting, unless it exceeds a given number of events within one hour (PA14), in which case it becomes a
manual-reset alarm.
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