Daikin UATYA-B, Operation Manual

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
3.11 Circuits and compressors
The start-up procedure and operating sequence are defined according to the number of refrigerant circuits and the number
of compressors featured.
Units may be supplied with either one or two refrigerant circuits and each circuit can fit either one or two compressors. One
of the compressors in the unit can be variable speed and inverter-controlled type.
All the parameters involved in these management methods are shown in the table.
Parameter Min Max UM Description
CF12 0 2 - Compressor type in circuit 1
CO1 0 999 s Minimum ON time
CO2 0 999 s Minimum OFF time
CO3 0 999 10 s Minimum time between 2 activations of the same compressor
CO4 1 999 s Time between the activation of 2 compressors
CO5 1 999 s Time between the deactivation of 2 compressors
CO16 0 1 - Criteria for selection of compressors in the selection of circuits
3.11.1 Starting and stopping of the compressors
Except in particular conditions, the compressors are started and stopped following a precise procedure.
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
CF12 0 - Compressor type in circuit 1
CO1 120 s Minimum ON time
CO2 180 s Minimum OFF time
CO3 30 10 s Minimum time between 2 activations of the same compressor
CO4 30 s Time between the activation of 2 compressors
CO5 15 s Time between the deactivation of 2 compressors
CO16 1 - Criteria for selection of compressors in the selection of circuits
After the unit has started, even though there is a thermoregulation request, the controller ensures compliance with the mi -
nimum OFF time of the compressors.
Below is the graph showing the actual thermoregulation demand and the respective compressor switch-ons and switch-offs
in units featuring 2 ON/OFF compressors.
Fig. 20 Compressor management times
In the graph, beside the parameters of the function, there are the abbreviations that refer to:
- Rqs = thermoregulation request
- R_St = actual status
- Unt = reference to the unit
- Cmp1 = reference to compressor 1
- Cmp2 = reference to compressor 2
3 Software functions