Stulz C7000 - Page 132

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EN/06.2019/G57 © STULZ GmbH – all rights reserved
C7000 INSTRUCTIONS fOR a/C UNITS
Differential temperature control of CW valve 1
Operate/Components/
Cooling/Valves/CW-control
Setpoint (return air)
This variant of differential temperature control can be used for A/C units of the CW2 version for which the
water circuit 1 is cooled by free cooling (dry cooler or cooling tower).
The valve opening degree is proportionally controlled according to the difference of the return air temperature
and the water inlet temperature. Start temperature = setpoint + DTC start. The proportional range is deter-
mined by the parameter "DTC range". The PID factors for the CW valve 1 are not considered.
The CW valve 2 is controlled independently from the above control according to the air temperature setpoint
by means of its PID parameters. Water circuit 2 can e.g be cooled by a chiller.
T
return air
– T
water inlet
Opening
degree
CW valve 1
NOTICE
If at least one of the values (Return air temperature or water inlet temperature) can-
not be measured, CW valve 1 will be opened 100%.
The following settings are necessary:
1. The parameter "mode" must be set on "DTC" (command:
cw
oper 3
).
2. Setting of the parameter "DTC start" (can also be left on "0").
3. Setting of the parameter "DTC range"
cw dtcstart 2.0
cw dtcband 3.0
Config/Components/Cooling/
Valves/CW-control
DTC