Full Charging Of Stratification Storage Tank - Siemens LMS14 User Manual

6.20.3.1.

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 requires at least 2 sensors. These are sensor B3 at the top of the storage
tank and sensor B36. Sensor B31 at the bottom can be used as an option. But this
sensor can also be used for a solar application only. In that case, sensor B36 must be
selected for full charging and parameter Full charging with B36 (5146) is to be set to
Yes.
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 the sensor at the top lies below
the switch-on threshold:
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 below the
switch-on threshold:
ON
DHW temp 1 (8830) < DHW temp setpoint (8831) – Switching diff (5024)
and
DHW temp 2 (8832) < DHW temp setpoint (8831) – Switching diff (5024)
During full charging, the burner's output is controlled to the temperature at sensor B36.
The charging setpoint is calculated from the DHW setpoint plus the parameterized
Intermediate circuit boost (5140):
Temperature charging setpoint = DHW temp setpoint (8831) + Intermediate circuit boost (5140)
During full charging, the pump in the primary circuit (boiler pump (Q1) or DHW charging
pump (Q3)) is constantly controlled with the parameterized Pump speed min (5101).
Ending a DHW request:
If sensor B36 is parameterized for detecting the end of full charging (Full charging with
B36 = Yes), full charging is ended when the temperature at sensor B36 exceeds the
charging setpoint by Excess interm circ temp max (5141), and the temperature
acquired by the sensor at the top reaches the DHW setpoint:
OFF
DHW temp 1 (8830) > DHW temp setpoint (8831)
and
DHW charging temp (8836) > Temperature charging setpoint + Excess interm circ temp max
(5141)
If sensor B31 at the bottom is installed and sensor B36 is not parameterized for
detecting the end of full charging (Full charging with B36 = No), full charging is ended
when the temperature at both storage tank sensors reaches the DHW setpoint:
OFF
DHW temp 1 (8830) > DHW temp setpoint (8831)
and
DHW temp 2 (8832) > DHW temp setpoint (8831)
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Building Technologies Division User Manual LMS14... CC1U7471en
6 The settings in detail 28.01.2015