Trane 4TXM2318BF300AA Service Manual page 126

After oil return in cooling mode, the quit condition of refrigerant eliminated:
OR
Oil return procedure in heating mode:
Send oil return signal
Inverter compressor
indicated FQCY
Outdoor motor
4-way valve
All expansion valves
auto angle
All indoors ON
Quit condition of oil return:
OR
1 minute later after oil return is over
Td Tc
＆ ‐ ＞30℃
OR Ts Tc2AVE
‐
Tc2AVE＜ 35
Max. 10 minutes
oil return begins
60s
oil return FQCY
0HZ
5s
AUTO
ON
OFF
450pulse
OFF
Max. 9 minutes (E)
OR Td Tc ‐ ＜20 ℃ for 30s continuously(5 minutes later, begin
to count)
Ts Tc2AVE
＆ ‐
begin to count)
Running for min. 5 minutes(E)
＞30℃
‐ ℃
AUTO (TC control)
350pulse(E)
＜15℃for 30s continuously(5 minutes later,
124
oil return over
60s soft startup
0HZ
AUTO
15s
450pulse
auto angle
anti-freezed startup