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Siemens Building Technologies Basic Documentation RVD110, RVD130 CE1P2381E
HVAC Products 13 Function block Actuator room heating 27.05.2004
13 Function block Actuator room heating
13.1 Operating lines
Line Function, parameter Unit Factory setting Range
91 Actuator running time s 120 10...873
92 P-band K 35 1...100
93 Integral action time s 120 10...873
94 Setpoint boost for control of the common flow °C 10 0...50
95 Max. limitation of flow temperature °C --- Variable...140
96 Min. limitation of flow temperature °C --- 8...variable
13.2 Mode of operation
This function block controls the motorized valve through which, with plant types no. 1, 4
through 6 and 8, the space heating circuit is controlled
• Plant type no. 1 has no d.h.w. heating. The heat exchanger only delivers heat to the
space heating circuit. The function block controls actuator Y1
• With plant types no. 4 through 6, there are 2 separate heat exchangers, one for the
heating circuit and one for the d.h.w. circuit. The function block controls actuator Y1
• With plant type no. 8, the space heating circuit has its own mixing circuit. The func-
tion block controls actuator Y5
In addition, the function block ensures minimum and maximum limitation of the respec-
tive heating circuit’s flow temperature, which is acquired as follows:
• With plant types no. 1 and 4 through 6: With sensor B1
• With plant type no. 8: With sensor B71
13.3 Control process
If the actual flow temperature deviates from the heating circuit’s setpoint, the 2-port
valve in the primary return offsets the deviation in a stepwise fashion. The controller
drives the valve’s electric 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 91 through 93, depending on the type of plant.
With plant type no. 8, a setpoint boost for the control of the heat exchanger (sensor B1,
actuator Y1 in the primary return) must be entered on operating line 94.
13.4 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 95.
At the limit value, the heating curve is horizontal, preventing the flow temperature set-
point from exceeding the maximum value.
This function can be deactivated.
The maximum limitation is not a safety function. For that purpose, a control thermostat
or thermal reset limit thermostat is required.
13.5 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 96.
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
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