Trane 4TXK6518G1000AA - Oil Return and EEV Control

9.4.4 Oil return control
Control purpose: Make the system oil regularly return to the compressor when the compressor work in a low
frequency.
Condition:
When the indoor units are working, if the compressor continuous frequency is lower than the parameters C HZ (E)
and the temperature TC is lower than 50°C (E) ,and it lasts 5 hours. Unit will enter oil return mode. When changing
the mode or manual stop or protective stop, time will pause. After the compressor restart, it will continue to time.
When timing, if the compressor working frequency is higher than B HZ (E) and lasts more than 10 minutes, the time
reset.
When heating, the time will reset if the defrost mode work.
After oil return, oil return timer reset
Process control chart of oil return:
After oil return, the condition of end of refrigerant ruled running
Oil return after 1 minutes
Td-TC>30°C Ts-TM>30°C
TM<-35°C
Send oil return signal Start End
60S
R
efrigerant ruled working
3 0 s
Oil return frequency B Hz( E) Auto
4 0 H Z
(
E
)
Inverter compressor
Auto frequency
300 pulses(E)
PMV Auto opening
120
pulse
s
(
E
)
OD fan
Auto working
Auto working
Auto working
ID fan
Auto working Auto working Auto working
4-way valve OFF OFF
OFF
SV valve (auto running according to some condition)
A u t o
O R