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5.2.9 Antifrost heater (optional)
5.2.9 Antifrost heater (optional)
5.2.9 Antifrost heater (optional)
5.2.9 Antifrost heater (optional)
5.2.9 Antifrost heater (optional)
In the event of an antifrost alarm, the antifrost heater is automatically energised.
The heater remains energised as long as the conditions causing the alarm persist.
While the alarm will only be given when the unit is switched on, the output of the antifrost heater will remain
enabled even when the unit is in stand-by status.
5.2.10 Compressors
5.2.10 Compressors
5.2.10 Compressors
5.2.10 Compressors
5.2.10 Compressors
When the unit is operating correctly (without any general alarm active) and the water temperature requires, the
microprocessor can activate the compressor outlets.
The compressors and relative step capacity operation are activated with a time delay in order to prevent high
breakaway current.
Before activating a compressor the controller checks the delivery pressure on the basis of the value read by the
transducer and the status of the high pressure switch. A check is also made of the compressor motor winding
temperature by verification of the status of the overload switch input.
When the compressor has been activated, the opening of the one of the above digital inputs causes its immediate
shutdown and the display of the relative alarm.
During compressor operation, delivery and suction oil pressure ratings are checked by the respective probes.
5.2.11 High and low pressure alarms
5.2.11 High and low pressure alarms
5.2.11 High and low pressure alarms
5.2.11 High and low pressure alarms
5.2.11 High and low pressure alarms
Delivery (high) pressure, suction (low) pressure are checked by the controller by means of probes.
When the compressor is operating, the controller checks that:
- delivery pressure is always below the safety value during cooling and during heat pump operations. In the event
that these values are exceeded, the controller immediately shuts down compressor operation and displays a
high pressure alarm. This alarm can be removed manually on the controller only when the pressure rating read
by the delivery pressure probe has dropped below the value that caused the shutdown, less the high pressure
differential.
- suction pressure is always higher than the safety value during cooling and heat pump operations. In the event
that the values read by the suction pressure probe are lower than safety values in the relative operating mode,
the controller immediately shuts down compressor operation and displays a low pressure alarm. This alarm is
not instantaneous, and is disregarded with relative delays at unit start-up and during operation. The suction
pressure alarm can be cancelled either automatically or manually, depending on the prearranged operating
mode. The number of compressor restarts can be set, before the intervention of the safety shut down of unit.
5.2.12 Compressor operation
5.2.12 Compressor operation
5.2.12 Compressor operation
5.2.12 Compressor operation
5.2.12 Compressor operation
When the unit is switched on, the first compressor is started up after a certain delay following pump start-up.
In any case, each compressor will operate for a minimum time, unless shut down by a serious alarm.
The alarms that can cause the compressor to shut down during the minimum operating time are the high pressure
alarm and the compressor overload alarm.
Once shut down, the compressors can only be restarted after the minimum shutdown time has elapsed, and in
any case after the minimum interval between two consecutive compressor start-ups has elapsed.
The consecutive start-up of two compressors, or the start-up of a compressor followed by the relative step capacity
operation will take place with a minimum delay equal to the time of step start-up.
The consecutive shutdown of two compressors, or the consecutive deactivation of the step capacity operations
and of the relative compressor, will be carried out with delays equal to the time for step deactivation.
5.2.13 Compressor and step capacity control
5.2.13 Compressor and step capacity control
5.2.13 Compressor and step capacity control
5.2.13 Compressor and step capacity control
5.2.13 Compressor and step capacity control
Compressor outputs are enabled by the controller in accordance to variations in reference water temperature in
relation to the set point.
The reference water temperature is normally the one read at the inlet on the chiller unit.
All outputs on the compressors and step capacity controls are regulated by the controller as power steps:
Summary of Contents for KAPPA V 2001
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