Stulz C7000 - Page 81

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© STULZ GmbH – all rights reserved EN/06.2019/G57
C7000 INSTRUCTIONS fOR a/C UNITS
The corresponding commands:
Components/Cooling/Valves
CW-control/more
Chillersaver Function
For units which are equipped with a GE/CW valve (unit versions GE, ACW,
GCW, CW and CW2) it is possible to output an analog control signal 010V,
which is used by a chiller to raise the water temperature setpoint, a measure
which reduces the energy needed by the chiller.
At the consumer side, which means at the A/C unit that requires chilled water,
the GE/CW valve is fully opened at an adjustable value, so that the heat rejec-
tion with a higher water temperature is assured by a higher water flow.
The chillersaver function is enabled by the assignment of an analog output to
the chiller saver signal and by setting a start and stop value for the signal under
the condition that the stop value is bigger than the start value.
Of course the chillersaver function must also be enabled at the chiller.
In the GE/CW valve Config menu you can adjust the analog output for the chill-
ersaver signal. In the second line of the menu beside you can set the start value
as a temperature difference to the GE/CW valve start value
➑ (temperature
setpoint of A/C unit + start temperature). At this value 0V are output on the
assigned output and the chiller sets its highest water temperature setpoint.
In the third line you can set the stop value
➒ as a temperature difference to the
start value. At this value 10V are output on the assigned output and the chiller
sets its lowest water temperature setpoint. Between the start and stop value
the chillersaver signal rises linearly. The WT setpoint at the chiller is reduced
respectively.
Adjusting an opening degree different from zero, at which the GE/CW valve is
opened 100% is not necessary indeed for enabling the chillersaver function,
however expedient. You can set this opening degree in the first line
➐.
When the A/C unit is in dehumidifying mode and the water temperature is
appropriate for dehumidification, the GE/CW valve is opened 100% and the
chillersaver signal is switched off. (0% = 0V = highest chiller WT setpoint).
cw sav100 30
cw savstart 0.2
cw savend 1.4
Operate