Operation Manual

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Siemens Schweiz AG User Manual CE1U2354en
HVAC Products Cooling circuit 23. August 2007
The cooling circuit pump is activated again as soon as the room temperature returns to
a level above the current room temperature setpoint.
While the “Room temperature limitation“ function is active, no cooling request is sent to
the heat source.
The function is deactivated in the following circumstances:
•
No room temperature sensor
•
"Room temp limitation" = ---
•
"Room influence“ (928) = --- (weather compensation only)
ON
TRKw-SDR
2355Z10
TRKw
TRx
P
OFF
°C
TRx Actual value room temp
TRKw Room temp. setpoint cooling
(with summer compensation)
SDR Room switching differential
P Pump
t Time
Mixing valve control
Line no. Operating line
938 Mixing valve cooling offset
939 Actuator type
2-position ¦ 3-position
940 Switching differential
2-pos
941 Actuator running time
945 Mixing valve in heating mode
Control ¦ Open
The refrigeration demand from the mixing valve circuit to the heat source is reduced by
the value set here. The purpose of this reduction is to enable the mixing valve controller
to compensate for the fluctuation in temperature caused by the heat source (2-point
control action).
2-position
The controller drives the actuator with only 1 relay output. When the output delivers a
signal, the valve opens. When there is no signal, the valve will close automatically.
3-position
The controller drives the actuator with 2 relay outputs. 1 of the outputs is used for
opening the valve and 1 for closing the valve.
For the 2-position actuator, the "2-position switching differential" must also be adapted.
Three-position actuators are not affected by the switching differential.
For the 3-position actuator, the running time of the mixing valve actuator can be
adjusted. The actuator running time has no effect on two-position actuators.
Defines the position of the mixing valve (Y1/Y2) when heating mode is active.
This parameter has no effect in systems with hydraulically separate heating and cooling
circuits.
Mixing valve cooling offset
A
ctuator type
Switching differential
2-pos
A
ctuator running time
Mixing valve in heating
mode