Daikin UATYA-B, Руководство по эксплуатации

Страница: 70 / 126

70
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:
- Pcond = condensing pressure;
- As% = opening signal percentage for external/exhaust air.
In normal operating conditions the signal controlling the external air and exhaust air dampers can range from the min.
setpoint stored in parameter “DA12” to the max. setpoint in parameter “DA13” (opening of the recirculated air damper is
complementary).
If the condensing pressure decreases and reaches the setpoint stored in parameter “DA32”, the value of the damper ope
-
ning signal is limited.
Within differential “DA33” the signal is linearly limited between the min. and max. setpoint values stored in parameters
“DA36” and “DA37” respectively.
After limiting the damper opening value, the signal is fixed at the value set in parameter “DA37” for the entire differential
stored in parameter “DA40”, if the condensing pressure rises above the setpoint in parameter “DA32”.
The damper opening signal starts following the ongoing opening percentage again only after the condensing pressure va
-
lues rise above the sum “DA32”+ “DA40”.
If the demand for damper opening limitation comes from the condensing and evaporating pressure values
simultaneously, the air flow is controlled using the lowest signal of the two.
If defrosting is started following the drop in the temperature converted from the evaporating pressure, safe
air flow control (ref. last graph) is met only if parameter “DA14” is equal to 0.
The function that limits damper opening as a result of the condensing and evaporating pressure has priority
over all the other functions (free cooling, free heating, CO
2
and VOC).
3.14.5 Min. opening in relation to external air temperature
In addition to the normal min. opening percentage of the external air and exhaust air dampers set in parameter “DA12”, the
controller includes the possibility to set the min. opening value in connection with the external air temperature.
If the temperature is lower than the setpoint in parameter “DA44” or higher than the setpoint in parameter “DA43”, the new
min. opening percentage of the dampers after the delay time set in parameter “DA46” is the value stored in parameter
“DA45”.
3.14.6 Min. opening in connection with dehumidification
The min. opening percentage of the external air dampers and the exhaust air dampers during normal operation is the value
set in parameter “DA12”; during the dehumidification cycle the reference percentage is the setpoint stored in parameter
“DA48”.
If the dehumidification function is enabled simultaneously with the function that reduces the min. damper
opening percentage in connection with the external air temperature, the controller adjusts the dampers ac -
cording to the lower value between the percentages set in parameters “DA45” and “DA48”.
3.14.7 Management of external air damper during defrosting
For continuous comfort in the room, the external air and exhaust air dampers can be overridden to close using the value
set in parameter “DA14”. This is the case when defrosting takes place reversing the refrigeration cycle, for as long as the
coil of the 4-way valve in the refrigerant circuit is de-energised. As a consequence, the recirculated air damper is fully open.
3 Software functions