Daikin UATYA-B, Руководство по эксплуатации

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
“cascade” temperature control.
If parameter “ST11” is set to “1”, “Cascade” control is enabled.
This function fulfils the system demand and keeps the air temperature in the delivery line within comfort values.
For this purpose, a virtual setpoint is calculated from the stored setpoint, as corrected with the air temperature in the return
line.
The setpoint is corrected dynamically as the air temperature changes in the return line.
The parameters involved in cascade temperature control are shown in the table.
The values of the parameters are representative. In specific cases, different values can be set.
Parameter Value UM Description
ST42 24.0 °C Cascade control - Unit setpoint
ST43 0.5 °C Mechanical cooling - Cascade control - Mode switching offset
ST44 4.0 °C Mechanical cooling - Cascade control - Operating differential
ST45 15.0 °C Mechanical cooling - Cascade control - Min. delivery setpoint
The graph below illustrates cascade control.
Spd °C
ST45
ST43
Tra °C
ST44
ST42
ST42
AOC
Fig. 5 Change of air delivery setpoint with “cascade” control in cooling mode
In addition to the parameters listed in the table, the abbreviations in the graph are:
- Spd = air setpoint in delivery line;
- Tra = air temperature in return line;
- AOC = automatic mode switching.
If the air temperature in the return line is higher than the sum of the setpoints in parameters “ST42”+ “STH43”, the value of
the air setpoint in the delivery line is reduced gradually to go from the value in parameter “ST42” to the value in parameter
“STH45”, within the differential set in parameter “STH44”.
3 Software functions