Trane 4TXM2318BF300AA Service Manual page 125

6.6.10 3.2.11 .
Oil return operation control
MULTI:
Unitary:
D: Entering condition
A
Entering condition
When the compressor running frequency is lower than 58Hz (E) continuously for 8 hrs, the system
When the compressor running frequency is lower than 58Hz continuously in all and outdoor
will enter oil return operation. In the course of mode changeover, manual unit stop or protective
unit stop, the time will be accumulative. After the compressor restarts up, the time will be counted
unit Tcm is lower than 50 degree for 5 hours, the system will enter oil return operation. In the
continuously. In a continuous 8 hrs, if the compressor running frequency is not less than 72Hz for
course of mode changeover, manual unit stop or protective unit stop, the time will be
over 10 minutes continuously, the accumulative time will be cleared. Also after the heating
accumulative. After compressor restarts up, the time will counted continuously. In counting
defrosting, the time will be cleared.
time for 5 hour, if the compressor running frequency is over 80Hz for 10 minutes continuously,
the time will be cleared. Also after the heating defrosting , the time will be cleared.
E: Procedure
Cooling mode: refer to "the oil return procedure in cooling mode"
B
Procedure
Heating mode: refer to "the oil return procedure in heating mode"
Cooling mode: refer to "the oil return procedure in cooling mode"
Heating mode: refer to "the oil return procedure in heating
F: The protection treatment in oil return operation
C
The protection treatment in oil return operation:
In the course of oil return, because of protection or abnormal unit stop, after the unit restarts up,
In the course of cooling oil return, because of all kinds of protection or abnormal unit stop,
the time will not be cleared, the system will need another oil return operation. In the refrigerant
after the unit restart, the time will not be cleared, the system need another oil return operation.
flow course in the oil return of cooling mode or after the oil return, and within 5 minutes after the
refrigerant being eliminated is over, the anti-freezed protection is invalid, and also the low voltage In the refrigerant flow course in oil return of cooling mode or after oil return, and within 5
protection is invalid. But the other protection is valid.
minutes after the refrigerant being eliminated is over, the anti-freeze protection and low
In the course of oil return from heating mode to cooling mode, if abnormal condition occurs or the
pressure protection are invalid, other protection is valid.
unit stops for protection, then the system needs not another oil return within 3 minutes after the
In the course of heating oil return ,because of all kinds of protection or abnormal unit stop, the
unit stops and it will start up directly, then to heating mode.
system need not another oil return operation after the unit stop for 3 minutes and enter in
In the course of oil return from heating mode to cooling mode, the anti-freezed protection is null
heating mode directly. In the course of changing to cooling oil return, the anti-freeze
and void, and the low voltage protection is null either. The other protection is valid.
Oil return procedure in cooling mode:
protection and low pressure protection are invalid, other protection is valid.
Oil return procedure in cooling mode:
Send oil return signal
Send oil return signal
Inverter compressor
running indoor PMV
Inverter compressor
outdoor unit PMV auto open angle
stopped indoor PMV
Outdoor motor
Outdoor fan motor auto operation
running indoor motor AUTO
running indoor motor auto operation
stopped indoor motor STOP
stop indoor motor
4-way valve
4-way valve
oil return begins
60s oil return beginning
Oil return frequency
60S
80 Hz（E）
auto frequency
auto angle
auto FQY
OFF angle 5(E)
AUTO
AUTO (TC or ambient temp. control)
auto（TC or ambient control）
AUTO (set fan speed)
auto（set fan speed）
stop
OFF
OFF
mode"
ref.eliminated
350pulse(E)
40HZ（E）
300pulse （E）
80(E)
OFF angle 5(E)
120pulse（E）
STOP
stop
OFF
OFF
123
oil return over
ref. eliminated oil return over 30s
auto frequency
Low frequency
30s
auto angle
120pulse(E)
auto open angle
AUTO
auto operation
AUTO
auto operation
STOP
stop
OFF
OFF