Compressor Step Control; Electronic Expansion Valve Control - Daikin RXYQ-TA Series Service Manual

Basic Control
5.4

Compressor Step Control

The actual rotation speed per second of the compressor (rps) depends on the type of compressor:
Compressor
JT1GCVDWYR
JT15JBVDWYR
JT100GCVDKW
JT150JBVDW
The change of compressor capacity step corresponds to 1 rps / step.
The control can skip an number of steps to reach faster the target saturated temperature.
5.5

Electronic Expansion Valve Control

Electronic expansion valve Y1E
Cooling: electronic expansion valve is used only at fully closed or fully open condition:
Compressor(s) OFF: fully closed (0 pulse)
Compressor ON:
Fully open (3,000 pulses): if level difference outdoor above indoor units within 50 m (164 ft)
(field setting 2-49-0).
Limited open: if level difference outdoor maximum 90 m (295 ft) above indoor units (field setting 2-49-1).
Inverter
compressor
Main
Y1E
Heating: electronic expansion valve is used in PID control suction superheat:
Compressor(s) OFF: fully closed (0 pulse)
Compressor ON:
At startup: closed (check suction pressure drops)
Modulated opening by:
Inverter
compressor
Main
Y1E
59
Actual rotation speed
rps = frequency/2
rps = frequency/3
rps = frequency/2
rps = frequency/3
0 Hz
3,000
Pulses
0
Suction superheat = accumulator inlet temperature – evaporating temperature.
Discharge superheat = discharge pipe temperature – condensing temperature.
Preventive change when compressor capacity step changes.
Limited opening when condensing temperate exceeds target condensing.
0 Hz
3,000
Pulses
0
TAYDU
72 96/120 144/168
–
– –
– – –
– – –
SiUS341615E
TATJU
72 96/120 144/168
– – –
– – –
–
– –
Functions and Control