Daikin UATYA-B, Operation Manual

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Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
3.12 Circuits and compressors - Functions
The controller is fitted with functions that get activated in special conditions in order to ensure correct compressor operation.
All the parameters involved in these control functions are shown in the table.
Parameter Min Max UM Description
CO46 0 180 min Oil return function - Delay in activation of “override compressors to ON”
CO47 0 180 min Oil return function - Override compressors to ON time with function active
CO48 25 100 % Oil return function - Capacity override percentage with function active
CO49 25 100 % Oil return function - Percentage inverter threshold to activate function
If parameters “CO46” and “CO66” are set to “0”, the corresponding functions are disabled.
3.12.1 Oil return for compressors managed with inverter
The values of the parameters are representative. In specific cases, different values can be set.
Parameter Value UM Description
CO46 30 min Oil return function - Delay in activation of “override compressors to ON”
CO47 3 min Oil return function - Override compressors to ON time with function active
CO48 75 % Oil return function - Capacity override percentage with function active
CO49 35 % Oil return function - Percentage inverter threshold to activate function
If the required cooling capacity involves operation of the compressor at a percentage lower than the value set in parameter
"CO49", after the delay time set in parameter "CO46" has elapsed, the controller forces the operating percentage of the
compressor to the value set in parameter "CO48" for a minimum time equal to the value set in parameter "CO47".
A graphical representation of the function is shown in the illustration.
Fig. 24 Forcing of frequency for oil recovery
In addition to the parameters in the table, the following abbreviations appear in the figure:
- "IS" = refers to the inverter frequency trends;
- "Req" = refers to the thermoregulation demand.
When operating in on-off mode below the value stored in parameter “CO49”, the count of the delay relating to parameter
“CO46” is in any case increased. The count of the delay relating to parameter “CO46” is only reset when the value is achie -
ved due to an override or during normal operation according to the value set in parameter “CO48”.
If the inverter compressor is connected in parallel with ON/OFF compressors, the minimum refrigerant speed required for oil
return is normally always guaranteed when an ON/OFF compressor is running at the same time as the inverter compressor.
3 Software functions