Daikin UATYA-B, Operation Manual

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
In addition to the parameters listed in the table, the abbreviations in the graph are:
- TeSdR = temperature sensed by probe in air return line;
- % = opening signal percentage for external/exhaust air.
If the external air temperature is lower than the temperature in the return line minus the value set in parameter “DA6”, the
unit is enabled for operation in free cooling mode.
If operation in free cooling mode is enabled and the reference air temperature for thermoregulation is higher than the
setpoint value in parameter “ST1” plus the offset value stored in parameter “DA8”, the controller increases the external air
percentage within the differential set in parameter “DA9”.
The setpoint ranges between the min. value stored in parameter “DA12” and the max. value in parameter “DA13”.
Damper opening may be limited with respect to the max. value set in parameter “DA13” as a result of problems with tempe
-
rature or pressure, as described in the chapter on limitations.
Thanks to the factory set parameters (“DA8” = -2; “DA9” = 2), the free cooling function keeps 100% outside
air until the setpoint is achieved.
When the reference air temperature is lower than the setpoint value, the free cooling function reduces the
opening of the outside air damper to the min. value.
A graphical representation is shown below.
DA8
DA9
DA13
DA12
%
ST1
TeSdR °C
Fig. 26 Damper command in free cooling mode
3.13.6.1 Winter free cooling
Free cooling may also be enabled when the unit is operating in heating mode through parameter “DA4”.
Winter free cooling is enabled if the air temperature in the return line is higher than the value in the summer setpoint “ST1”
and the conditions required for free cooling are met.
3 Software functions