Daikin UATYA-B, Operation Manual

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
Below is a graphical representation of the parameters involved in ventilation control in order to achieve and keep the pres -
sure difference stored in the setpoint at the measurement point.
FA52 FA53
FA57
FA58
Tvar s
FA49
Pdr Pa
FA52 FA54
Dec Inc
FA56
FA55
FA52 FA53
FA61
FA62
Avar %
FA49
Pdr Pa
FA52 FA54
Dec Inc
FA60
FA59
Fig. 16 Images showing the percentage and time variation as the pressure difference changes
In addition to the parameters listed in the table, the abbreviations in the graph have the following meanings:
- PdR = pressure measured at the reference point;
- Avar = percentage value of “amplitude” variation;
- Tvar = delay between two consecutive demands for ventilation variation;
- Inc = increment;
- Dec = decrement.
The controller measures the pressure difference at the reference point and compares it with the setpoint value stored in
parameter “FA49”.
A dead zone exists below and above the setpoint which corresponds to the value set in parameter “FA52”.
If the measured value is lower than the setpoint minus the dead zone (“FA49” - “FA52”), the controller calculates the per
-
centage increment and the delay between the two ventilation variations using the values set in the relevant temperature/
humidity control parameters.
If the measured value is higher than the setpoint plus the dead zone (“FA49” + “FA52”), the controller calculates the per -
centage decrement and the delay between the two ventilation variations using the values set in the relevant temperature/
humidity control parameters.
The percentage ventilation is always limited by the minimum and maximum values set in parameters “FA7” and “FA8” re -
spectively.
According to the values shown in the graphs, the greater the distance between the measured pressure difference and the
setpoint, the higher the speed percentage variation and the shorter the time between two consecutive variations. On the
other hand, the smaller the distance between the measured pressure difference and the setpoint, the smaller the speed
percentage variation and the longer the time between two consecutive variations.
3 Software functions