Toshiba MMY-MUP0961HT6P-UL Service Manual page 55

Item Description of operation, numerical data, and other information
3. Capacity 1) The compressors of the header and follower units are controlled on the basis of
control capacity demand issued by indoor controllers.
2) The two compressors featured in an outdoor unit operate on a rotational basis, so
that, every time they come to stop, their order of startup changes.
3) When one or more follower outdoor units are connected, the system will be started
next time between all the outdoor units including the header outdoor unit when the
system is stopped (including thermostat-off) or the power is reset while 24 hours or
more has passed on the accumulated operating time. Reverse the priority of time.
4. Oil level 1) TK1,2 sensor detection temperature and prediction TK1, 2 sensor temperature is used
detection to judge whether there is an appropriate amount of oil in the compressor case. This
control control is performed independently by the header outdoor unit and follower outdoor units.
2) Based on the relationship between the TK detection temperature of the compressor
into and the predicted TK sensor temperature, it is judged whether the oil level in the
compressor case is appropriate, and if it is insufficient, the upper limit of the
compressor speed and SV3D valve operate.
3) If the shortage is not resolves by the operation of 2), shift to the oil recovery operation.
4) This control function is performed whenever at least one compressor is in operation.
Oil separator
SV
SV3D
SV
SV41
TD2
TD1
Comp1
TK1
TK2
Accumu
SV lator
SV42
SV3F
Comp2
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Remarks
• The outdoor rotation
control may be performed
even when the insufficient
refrigerant state is not
released even if the indoor
refrigerant recovery control
is performed.
• The predicted TK sensor
temperature is the
predicted value of the TK
sensor temperature when
the oil is in proper condition
• SV3D valve: Solenoid valve
for oil return of oil separator
• Oil level judgment
1
guide When predicted
TK-TK < 50°F(10°C),
the oil level is
appropriate When
2
predicted TK-TK ≥
50°F(10°C), the oil
level is insufficient
• Predicted TK1, 2 and TK1,
and 2 sensor temperature
It can check by
"8-6. 7-Segment Display
Function".
• The TK sensor detection
temperature and the
predicted TK sensor
temperature can be found
in the the 7-Segment
Display Function
(8.6.7(33)).