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Siemens Building Technologies
Basic Documentation RVD110, RVD130
CE1P2381E
HVAC Products
12 Function block Actuator heat exchanger
27.05.2004
12
Function block Actuator heat ex-
changer
12.1 Operating lines
Line
Function, parameter
Unit
Factory setting
Range
81
Actuator running time, actuator Y1*
s
120
10...873
82
P-band of control, actuator Y1*
K
35
1...100
83
Integral action time of control, actuator Y1*
s
120
10...873
85
Max. limitation of flow temperature
°C
---
Variable...140
86
Min. limitation of flow temperature
°C
---
8...variable
12.2 Mode of operation
This function block controls the motorized valve through which, with plant types no. 2,
3, 7 and 8, the heat exchanger is controlled. This is the heat exchanger which, via the
common flow, supplies heat to both the space heating circuit and the d.h.w. circuit. The
respective actuator is actuator Y1.
In addition, this function block ensures minimum and maximum limitation of the com-
mon flow temperature acquired with sensor B1.
12.3 Control
process
If the actual flow temperature deviates from the setpoint, the 2-port valve in the primary
return offsets the deviation in a stepwise fashion. The controller drives the valve’s elec-
tric or electrohydraulic actuator whose ideal running time is 2 to 3 minutes.
The actuator’s running time, P-band and integral action time must be entered on oper-
ating lines 81 through 83, depending on the type of plant.
12.4 Maximum limitation of the flow temperature
The setting range for the maximum limit value lies between the minimum limit value and
140 °C. The maximum limit value is to be entered on operating line 85.
At the limit value, the heating curve runs horizontal, preventing the flow temperature
setpoint from exceeding the maximum value.
This function can be deactivated.
Maximum limitation is not a safety function. For that purpose, a control thermostat or
thermal reset limit thermostat is required.
12.5 Minimum limitation of the flow temperature
The setting range for the minimum limit value lies between 8 °C and the maximum limit
value. The minimum limit value is to be entered on operating line 86.
At the limit value, the heating curve runs horizontal, preventing the flow temperature
setpoint from falling below the minimum value.
This function can be deactivated.
Note
