Daikin UATYA-B, Operation Manual

Page: 45 / 126

45
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.
RFA52 RFA53
RFA57
RFA58
Tvar s
RFA49
Pdr Pa
RFA52 RFA54
Dec Inc
RFA56
RFA55
RFA52 RFA53
RFA61
RFA62
Avar %
RFA49
Pdr Pa
RFA52 RFA54
Dec Inc
RFA60
RFA59
Fig. 19 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 “RFA49”.
A dead zone exists below and above the setpoint which corresponds to the value set in parameter “RFA52”.
If the measured value is lower than the setpoint minus the dead zone (“RFA49” - “RFA52”), the controller calculates the
increment percentage and the delay between the two ventilation variations using the values set in the relevant setup para -
meters.
If the measured value is higher than the setpoint plus the dead zone (“RFA49” + “RFA52”), the controller calculates the
decrement percentage and the delay between the two ventilation variations using the values set in the relevant control
parameters.
The ventilation percentage is always limited by the minimum and maximum values set in parameters “RFA7” and “RFA8”
respectively.
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.
If the temperature/humidity control parameters need to be edited, the new entered values must be consi -
stent with the set parameters.
3 Software functions