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Siemens Building Technologies
Basic Documentation RVA63.242, RVA53.242
CE1P2373E
Landis & Staefa Division
Description of heating engineer settings
26.03.2001
4.60 Release integral for boiler sequence
Variant for switching on the heat sources in the cascade.
Setting of the heat deficit for releasing an additional boiler.
Setting range
Unit
Factory setting
0...500
°C (K) min
200
The setting defines the heat deficit required to on switch an additional boiler.
Increasing the value:
An additional boiler will be switched on less quickly.
Release will take place only when the heat deficit is greater.
Decreasing the value:
An additional boiler will be switched on more quickly.
Release will already take place when the heat deficit is
smaller.
When, with the boilers currently in operation, the amount of heat produced falls short of
demand by the release integral set here, another boiler will be switched on.
4.60.1 Temperature-time integral
The temperature-time integral is a continuous summation of the temperature differential
over the time. In this case, the decisive criterion is the difference by which the
temperature falls below the cascade flow temperature TVKw-(SDK/2-TVKx).
Switching point
Through the generation of the temperature-time integral it is not only the period of time
that is considered, but also the extent of the undershoot. This means that when the
crossing is significant, another boiler will be released earlier.
When the release integral (area "a“ in the diagram below) has reached the value set
(point in time tF), another boiler will be released.
50
48
52
TVKx
2371Z31
°C
44
46
t
TVKw+SDK/2
a
TVKw
TVKw-SDK/2
tF
a
Release integral for boiler sequence
TVKw
Flow temperature setpoint of cascade
TVKx
Actual value of cascade flow temperature
t
Time
tF
Time of release
SDK
Switching differential of the boiler
Benefit
Description
Setting
Effect
Switching on
Example: