KGL Operating Manual – VS 3010 BS
2018-07-02
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60 178
4.6.1.14 Alarm due to implausible opening degree
The message “Check OD” is triggered under the following conditions:
The minimum superheat has been undercut for 30 minutes
An opening degree of 100% is active for 30 minutes while the temperature at the cascade inlet (R5.1) is
greater than the tc-Z2 setpoint. If the R5.1 sensor is not connected, no alarm signalling takes place
even if the opening degree of 100% is present for longer than 30 minutes.
The priority of the "Check OD" message can be parametrised.
4.6.2 Control of the cascade by a case controller
If the pack controller is used for compressor packs in which both temperature ranges regulate in the plus
range, a plate-type heat exchanger can be use for an LT consumer. The plate-type heat exchanger cascade
has the task of dissipating the condensing heat of the LT circuit on the Z1 compressors. In order to avoid
pressure faults in the LT circuit, the LT refrigeration point may only be enabled if a Z1 compressor is switched
on. If the system is also equipped with a suction gas bypass, the refrigeration point can be enabled if any Z1 or
Z2 compressor is operating.
The disabling and the enabling are performed by consumer enable via the CAN bus. The CAN bus address
(node number) 1..99 of the LT refrigeration point can be specified with the parameter "KN.Nr.Kaskade" (menu
3-1). The input of "---" (factory setting) for "Kn.Nr. Kaskade" deactivates the function.
4.7 Heat recovery mode
The heat recovery mode of the pack controller is realised using the following parameters:
The HR mode is activated/deactivated using the parameter Ht. rec.mode Y/N (menu 3-1). After the
activation of the Ht. rec.mode parameter, the digital input 22 (heat recovery / burst disk, terminals 92
/93) is used for the request of the heat recovery mode. Otherwise, the input is used for acquiring the
status of the burst disk.
The parameter HR max. (menu 3-3-2) specifies the maximum condensing temperature that is permitted
to be reached during HR mode.
The temperatures are converted to pressures of the selected refrigerant for the regulation.
The parameter HR dif. (menu 3-3-2) defines a temperature difference. If the pressure increases to a
level greater than HR mac., the first fan stage is loaded immediately (the configured control times are
ignored).
Every further fan stage is loaded after expiry of the basic load time (the variable control time is ignored)
If the pressure drops to a level lower than HR max. - HR dif., fan stages are unloaded taking account of the
basic and variable unload times. The heat recovery mode is activated via the digital input 22 (terminals 92/93).
