SDC / DHC
Hydraulic Components
EN2H-0221GE51 R0812
183
Special mixing circuit functions (district heating control
devices only)
By setting an additional return sensor in the mixed heating circuit,
the return temperature can be limited using this function. This is a
maximum temperature limit.
With some applications, an excessively high return temperature
causes problems (e.g. district heating or condensing
applications). They can occur if heat is not being extracted in the
occupied room (e.g. thermostat valve closed).
If the return temperature exceeds the set maximum value, the
mixed heating circuit valve is adjusted to this maximum
temperature. The flow temperature then remains ignored.
7.3.4.10.1 Mixed heating circuit control
7.3.4.10.1.1 Proportional part Xp
The proportional band Xp defines how a step change of the
setpoint effects a change of the corresponding actuator according
to the selected setting.
Example:
Consider an actuator moving though an angle of 90°C in an action
time of two minutes. When a sudden flow temperature control
deviation of 10 K occurs (e.g. when the system switches from
reduced to daytime operation) and the P-part setting is 5%/K, the
actuator has to open by 50% (5%/K x 10 K). Consequently, the
duration of the actuation pulse is one minute (= 50% of the
actuator runtime).
Return limit
Summary of Contents for DHC
Page 1: ...EN2H 0221GE51 R0812 Smile SDC heating and district heating controller SERVICE MANUAL ...
Page 2: ...EN2H 0221GE51 R0812 ...
Page 10: ...Contents SDC DHC 10 EN2H 0221GE51 R0812 ...
Page 36: ...Operation SDC DHC 36 EN2H 0221GE51 R0812 Operating overview ...
Page 66: ...Operation SDC DHC 66 EN2H 0221GE51 R0812 ...
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