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:
- Pevap = evaporating 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 evaporating pressure decreases and reaches the setpoint stored in parameter “DA34”, the value of the damper ope
-
ning signal is limited.
Within differential “DA35” the signal is linearly limited between the min. and max. setpoint values stored in parameters
“DA38” and “DA39” respectively.
After limiting the damper opening value, the signal is fixed at the value set in parameter “DA39” for the entire differential
stored in parameter “DA41”, if the evaporating pressure rises above the setpoint in parameter “DA34”.
The damper opening signal starts following the ongoing opening percentage again only after the evaporating pressure va
-
lues rise above the sum “DA34”+ “DA41”.
3.14.4 Limitation based on condensing pressure in heating mode
When a refrigerant circuit in the unit is operating in heating mode, the condensing pressure may limit the damper control
signal.
The parameters concerned are shown in the table.
The values of the parameters are representative. In specific cases, different values can be set.
Parameter Value UM Description
DA12 30 % External air - FC / FH - Min opening
DA13 100 % External air - FC / FH - Max opening
DA32 10.00 bar
External air - Opening limitation - Winter oper. - Min cond. press. threshold for activa -
tion
DA33 1.00 bar External air - Opening limitation - Winter oper. - Min cond. press. diff. for activation
DA36 0 % External air - Opening limitation - Min opening for cond. press.
DA37 60 % External air - Opening limitation - Max opening for cond. press.
DA40 2.00 bar External air - Opening limitation - Deactivation diff. for cond. press.
A graphical representation is shown below.
DA32
DA37
DA13
DA12
%
Pcond (bar)
DA36
DA40 DA33
Fig. 34 Damper command in free cooling mode
3 Software functions