Daikin UATYA-B, Руководство по эксплуатации

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
3.17.1 Simultaneous or separate defrost
Taking for granted that parameter “DF1” is different from “0” and defrost is enabled, the procedure to defrost multi-circuit
units depends on their construction.
3.17.2 Check of conditions for the defrost cycle at fixed evaporating temperature
By measuring the operating values of the unit, the controller checks whether there are the conditions for which a defrost is
necessary.
The conditions for starting a defrost cycle are as follows:
- the evaporating temperature value must be lower than the threshold to start the defrost cycle, as set in parameter
“DF10”;
- the condition must be maintained for at least the time set in parameter “DF11”;
- the unit must have been running for at least the time set in parameter “DF17”;
- the time set in parameter “DF18” must have elapsed since performance of the last defrost cycle in the same circuit;
- if the defrost cycles have been performed in separate circuits, the time set in parameter “DF19” must have elapsed
since defrosting was performed in the last 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
DF1 1 - Defrost method
DF10 -12.0 °C Defrost start evaporating temperature
DF11 120 s Time defrost condition is maintained
DF17 10 min Delay to first defrost after the unit is switched on
DF18 30 min Minimum delay between two defrost cycles of the same circuit
DF19 10 min Minimum delay between two defrost cycles of different circuits
Do not change the set values without the manufacturer's approval.
3.17.3 Preparation for cycle reversal
If an air defrost cannot be done, the controller carries out a defrost with refrigeration cycle reversal by operating a 4-way
valve.
Depending on the set parameters, refrigeration cycle reversal can take place in different ways linked to the value of para
-
meter “DF30”.
Depending on the value set in parameter “DF30” cycle reversals may include:
- 0 = with 100% of the refrigeration capacity before reversal;
- 1 = with capacity reduction to the minimum refrigeration capacity before reversal;
- 2 = with compressor(s) not running.
The values of the parameters are representative. In specific cases, different values can be set.
Parameter Value UM Description
DF30 1 - Defrost entry method
DF31 60 s Forcing time of circuit at 100% on entering defrost mode (if DF30=0)
DF32 30 s Forcing time of circuit at minimum on entering defrost mode (if DF30=1)
DF33 20 s Forcing time of circuit OFF on entering defrost mode (if DF30=2)
Depending on the value set in parameter DF30, before refrigeration cycle reversal, the controller maintains the condition for
the time set in the values of parameters DF31 or DF32 or DF33.
3 Software functions