Daikin UATYA-B, Operation Manual

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
When the Night Shift System function is enabled during the set time bands and on the selected days, the ventilation speed
varies proportionally between the min. (“EFA6”) and max. (“EFA8”) values as the condensing temperature varies within
the setpoints stored in parameters “EFA30” and “EFA31”. The controller keeps the max. ventilation value if the condensing
temperature exceeds the value set in parameter “EFA31”.
Ventilation is always stopped as soon as the difference between the values in parameters “EFA9” and “EFA12” is achieved.
The control is not affected by the number of compressors in operation.
3.15.3 Evaporation control
During compressor operation in cooling mode the controller adjusts source-side ventilation to manage the evaporating pres -
sure. The adjustment varies according to whether one or two compressors are in operation in the circuit.
The adjustment is based on the evaporating temperature value calculated by conversion of the corresponding pressure in
the refrigerant circuit.
Units featuring two refrigerant circuits have an independent speed adjustment function in each circuit.
The parameters involved are shown in the table.
The values of the parameters are representative. In specific cases, different values can be set.
Parameter Value UM Description
EFA14 30 % Heating - Min. speed
EFA15 60 % Heating - Average speed
EFA16 100 % Heating - Max. speed
EFA17 15.0 °C Heating - Evaporation setpoint for min. speed/opening
EFA18 -6.0 °C Heating - Evaporation temperature for average speed/opening
EFA19 -12.0 °C Heating - Evaporation temperature for max. speed/opening
EFA20 5.0 °C Heating - Cut-off differential
EFA21 15.0 °C Heating - Offset
A graphical representation is shown below.
%
EFA21
TEvap °C
EFA20
EFA15
EFA14
EFA16
EFA18 EFA19 EFA17
1c
2c
Fig. 37 Graphical representation of air condensation control
In addition to the parameters listed in the table, the abbreviations in the graph are:
- Tcond = Condensing temperature
- % = percentage value of signal for fan control
- 1c = one compressor in operation
- 2c = two compressors in operation
3 Software functions