Daikin RXYQ-TA Series, Service Manual

Page: 72 / 337

Basic Control SiUS341615E
59 Functions and Control
5.4 Compressor Step Control
„
The actual rotation speed per second of the compressor (rps) depends on the type of compressor:
„
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).
„
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:
„
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.
Compressor Actual rotation speed
TAYDU TATJU
72 96/120 144/168 72 96/120 144/168
JT1GCVDWYR rps = frequency/2
z
–
zz
– – –
JT15JBVDWYR rps = frequency/3 –
z
– – – –
JT100GCVDKW rps = frequency/2 – – –
z
–
zz
JT150JBVDW rps = frequency/3 – – – –
z
–
0
Inverter
compressor
Main
Y1E
0 Hz
3,000
Pulses
Inverter
compressor
Main
Y1E
0 Hz
0
3,000
Pulses