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17 Description of function
38
99E13331xx-mub-en - V08
2022/07
17.2
Stratification (return stratification)
This function serves to improve the temperature
stratification in the storage tank or to avoid a temperature
mix. In the return can be considerable temperature
differences (for example, with an existing circulation).
Therefore, the return is connected to the storage tank via
a three-way valve.
According to this, the return is fed into the upper or the lower part of the storage tank,
depending on the position of the three-way valve.
For this function, 2 modes can be selected:
•
Thermostat mode
•
Differential mode
At
Stratification → Sensor selection
, you can select an external sensor as an alternative to the
cold water sensor for both modes. The external sensor must be mounted into the return ahead
of the three-way valve.
Operation mode "Thermostat mode"
If the switch-on temperature is exceeded at the cold water sensor, the controller activates the
relay for the stratification. The return is fed into the upper part of the storage tank.
If the temperature at the cold water sensor falls below the switch-off threshold (switch-on
temperature - hysteresis), the relay is switched off. The return is fed into the lower part of the
storage tank.
Operation mode "Differential mode"
In addition to the temperature at the cold water sensor, the storage temperature is required.
This temperature is measured exclusively via S3. If the temperature difference between the cold
water sensor and the storage tank sensor exceeds the value
Δ
T On, the controller switches on
the relay for the stratification. The return is fed into the upper part of the storage tank. If the
temperature difference between the cold water sensor and the storage tank sensor exceeds the
value
Δ
T Off, the the relay is switched off.
The return is fed into the lower part of the storage tank.
NOTICE
When the
Differential mode
is activated, the controller uses the sensor input S3 to measure
the storage tank temperature. The three-way valve has to be installed in such a way that in a
currentless state the flow direction is switched towards the colder part of the storage tank.
The storage tank sensor has to be installed in the warmer part of the storage tank.