Blue Box KAPPA V SR Installation, Operating And Maintenance Manual Download

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In conditions that lead to tripping the freeze alarm, the controller energises the heater.
The heater remains powered for the entire time that the conditions for the freeze alarm continue.
Unlike the low water temperature alarm, which is enabled only when the unit is powered on, the anti-freeze
heater can be energised when the machine is on stand-by.

5.2.10 Compressor operation

When the unit is running correctly and no general alarms are present, the microprocessor controller starts the
compressors in accordance with the water temperature reading.
Compressor starts are staggered in accordance with preset delay intervals, thus avoiding excess input current
surges.
Before starting a compressor, the microprocessor checks the value of the delivery pressure by means of the
relevant transducer, the status of the high pressure switch and the compressor motor windings temperature by
checking the thermal protection.

When the compressor has been started, tripping of any of the safety devices will cause the compressor to stop
immediately and an alarm will be displayed.
While the compressor is running, discharge pressure and suction pressure are monitored constantly by means of
the relevant sensors.

On unit start-up the first compressor is started with a delay, set on the microprocessor controller, after the start of
the hydraulic system circulating pump.
Once started, each compressor must run for a minimum operating period, unless a critical alarm should trip in the
meantime.
The critical alarms which can stop the compressor during the minimum operating time are the high pressure
alarm and the compressor thermal cut-out alarm. Once stopped each compressor can be restarted only after a
minimum idle time or after a minimum time interval between two consecutive starts has elapsed.
The consecutive starting of two compressors or the consecutive starting of one compressor, is executed with
minimum delay intervals equal to the capacity step activation time.
Stopping compressors is also performed with a minimum programmed delay interval.

5.2.11 Compressors and capacity steps management

Start-up of the compressors is automatic when the reference water temperature changes with respect to the
programmed set-point.
Normally the reference water temperature is the value detected at the inlet to the chiller unit.

Two different working possibities are available as cooling demand increases:

- In the “FPM” working system the first step of the first compressor is energised, then the first step of the second

compressor, then the first compressor operates at full load and finally the second compressor operates at full
load.

- In the “CPM” working system, the first step of first compressor is energised and than operates at full load, than

the first step of the second compressor starts and finally the second compressors operates at full load.

As the cooling demand reduces, the capacity steps are unloaded in reverse to the load procedure: in the “FPM”
system all compressors capacity steps reduce and the compressors are stopped, in the “CPM” mode for each
compressor the capacity steps are first reduced and then the compressors are stopped.

An even distribution of operating hours over all compressors of the the unit is ensured by selecting the automatic
lead/lag selection.

With the start rotation function active, the first compressor to start is the first one that previously stopped. The first
compressor to start will be the one with the least operating hours.

The capacity control of compressors can be carried out either by steps or continuously.