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Building Technologies Division User Manual LMS14… CC1U7471en
6 The settings in detail 28.01.2015
6.20.1 Stratification storage tank with control to the boiler
temperature flow
In the case of control to the boiler temperature setpoint, full charging requires a sensor
at the top (B3) and at the bottom (B31) of the storage tank. If the sensor at the bottom
is not installed, only recharging is possible, regardless of the parameterized Type of
charging (5022). When using control to the boiler temperature setpoint, sensor B36
must not be connected.
The boiler temperature setpoint is calculated from the current DHW temperature
setpoint and the parameterized Flow setpoint boost (5020):
Boiler temperature setpoint = DHW temp setpoint (8831) + Flow setpoint boost (5020)
The burner is switched on when the boiler temperature lies by at least the
parameterized Switching diff on DHW (2460) below the Boiler setpoint (8311). It is
switched off when the boiler temperature lies by at least the parameterized Switching
diff off min DHW (2461)/Switching diff off max DHW (2462) above the Boiler setpoint
(8311).
The output request to the burner is controlled between the parameterized Required
speed LF min (9525) and the maximum output in DHW mode Fan speed DHW max
(2444). If no maximum output for DHW mode is parameterized (OSV), the burner’s
maximum output Required speed HF max (9530) is available.
The DHW intermediate circuit pump (Q33) can be activated with a delay in relation to
the pump in the primary circuit. The delay is dependent on the rate of boiler
temperature increase. For this, Min start temp diff Q33 (5148) can be used to set a
temperature differential. The intermediate circuit pump is activated when the boiler
temperature reaches the level of current DHW setpoint minus the value set here (in the
case of a negative value), or when the boiler temperature exceeds the current DHW
setpoint by the value set here (in the case of a positive value).
ON
Boiler temp (8310) > DHW temp setpoint (8831) + Min start temp diff Q33 (5148)
If, subsequently, the boiler temperature drops below this limit, the intermediate circuit
pump still remains activated.
The temperature differential can be parameterized in the range from -20 °C to +20 °C. If
the temperature differential is set to OSV (---), the intermediate circuit pump is activated
with no delay in relation to the pump in the primary circuit.
If the pump in the primary circuit (boiler pump (Q1) or DHW charging pump (Q3)) is
configured as a modulating pump, it is constantly controlled with the parameterized
Pump speed max (5102)) with both types of charging.
When the Legionella function is active, the parameterized Legionella funct setpoint
(1645) is used as the DHW setpoint.
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