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Siemens Building Technologies Basic Documentation RVL471 CE1P2524E
HVAC Products 11 Function block "3-position actuator heating circuit" 23.10.2002
11 Function block "3-position actuator
heating circuit"
This function block provides 3-position control of the heating circuit. Depending on the
plant type, it acts as follows:
• Weather-compensated, on the mixing valve of a space heating system (plant type 1–x)
• Weather-compensated, on the valve in the primary return of a space heating system
with a district heat connection (plant type 3–x)
• Demand-compensated, on the mixing valve of a main flow (plant type 4–x)
• Demand-compensated, on the valve in the primary return of a main flow with district
heat connection (plant type 6–x)
11.1 Operating lines
Line Function, parameter Unit
Factory
setting
Range
81 Maximum limitation of flow temperature °C --- --- / 0...140
82 Minimum limitation of flow temperature °C --- --- / 0...140
83 Maximum rate of flow temperature increase °C --- --- / 1...600
84 Flow temperature boost mixing valve / heat exchanger °C 10 0...50
85 Actuator running time s 120 30...873
86 P-band of control (Xp) °C 32.0 1...100
87 Integral action time of control (Tn) s 120 30...873
11.2 Limitations
11.2.1 Flow temperature limitations
The following settings can be made:
• Maximum limitation of the flow temperature. At the limit value, the heating curve runs
horizontally. This means that the flow temperature setpoint cannot exceed the maxi-
mum value
• Minimum limitation of the flow temperature: At the limit value, the heating curve runs
horizontally. This means that the flow temperature setpoint cannot fall below the mini-
mum value (exception: with locking signals)
If the setpoint is limited, the display shows:
= for maximum limitation
= for minimum limitation
Both limitations can be deactivated (setting ---).
Minimum limitation is also active during storage tank charging, depending on the kind of
priority.
With plant types 3–1 and 3-3, where maximum limitation is not active during storage
tank charging.
Settings
Impact on d.h.w. heating
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