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Building Technologies Division User Manual LMS14… CC1U7471en
6 The settings in detail 28.01.2015
6.20.2.1. Full charging of stratification storage tank
With full charging, the entire content of the stratification storage tank is charged to the
current DHW setpoint.
Full charging with B36 (5146) can be used to define whether full charging shall be
ended when the DHW charging temperature rises. This setting makes sense when
sensor B31 at the bottom is used for a solar application. Otherwise, full charging is
ended via sensor B31 at the bottom.
Triggering a DHW request:
If sensor B31 is used for solar (Full charging with B36 = Yes) or is not installed, full
charging is started when the temperature acquired by sensor B3 at the top lies by at
least the parameterized Switching diff (5024) below the current DHW temp setpoint
(8831):
ON
DHW temp 1 (8830) < DHW temp setpoint (8831) – Switching diff (5024
)
If sensor B31 is installed and not used for solar (Full charging with B36 = No), full
charging is started when the temperature at both storage tank sensors lies by at least
the parameterized Switching diff (5024) below the DHW temp setpoint (8831):
ON
DHW temp 1 (8830) < DHW temp setpoint (8831) – Switching diff (5024)
and
DHW temp 2 (8832) < DHW temp setpoint (8831) – Switching diff (5024)
The setpoint for the charging temperature at sensor B36 is calculated from the DHW
setpoint plus the parameterized Intermediate circuit boost (5140):
Temperature charging setpoint = DHW temp setpoint (8831) + Intermediate circuit boost (5140)
First, the Boiler setpoint (8311) results from the DHW temp setpoint (8831) plus the
parameterized Flow setpoint boost (5020).
Internal boiler temperature setpoint = DHW temp setpoint (8831) + Flow setpoint boost (5020)
Setpoint compensation becomes active when the parameterized Flow setp
compensation delay (5142) has elapsed. The delay starts when the DHW intermediate
circuit pump (Q33) is switched on.
Setpoint compensation readjusts the initial boiler temperature setpoint (internally) in a
way that the temperature maintained at sensor B36 is the charging setpoint.
If the temperature acquired by sensor B36 remains below the charging setpoint,
setpoint compensation raises the Boiler setpoint (8311). If the temperature at sensor
B36 exceeds the charging setpoint, the Boiler setpoint (8311) is reduced.
Setpoint compensation is implemented in the form of a PID controller. Parameters Flow
setp compensation Xp (5143), Flow setp compensation Tn (5144), and Flow setp
compensation Tv (5145) are used as the controller coefficients. The temperature
acquired by sensor B36 serves as the control variable.
The Boiler setpoint (8311) is thus the result of the initial boiler temperature setpoint
(internally) plus the readjustment calculated by setpoint compensation:
Boiler setpoint (8311) = internal boiler temperature setpoint + correction value
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