Daikin UATYA-B, Operation Manual

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
3.3.4 Pre-heating coil
The controller is designed to manage a pre-heating coil: the temperature is set up based on the temperature sensed by the
mixed air probe.
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
STH1 20.0 °C Mechanical heating / Auxiliary heating in winter mode - Temperature setpoint
STH141 0.0 °C Preheating - Temperature offset
STH142 2.0 °C Preheating - Activation differential
STH143 0 % Preheating - Minimum request
STH144 100 % Preheating - Maximum request
A graphical representation is shown below.
%
SdR °C
STH142
STH144
STH143
STH1
100
STH141
0
Fig. 8 Graphical representation of proportional heating demand
In addition to the parameters listed in the table, the abbreviations in the graph are:
- Sdr = mixed air probe;
- %Av= valve opening percentage.
If the temperature of the mixed air is lower than the setpoint in parameter “STH1”, minus the “offset” value stored in para -
meter “STH141”, the controller increases the valve opening percentage to the coil, within the differential set in parameter
“STH142”.
Temperature control ranges between the min. value stored in parameter “STH143” and the max. value in parameter
“STH144”.
3 Software functions