Toshiba MMU-P0121H Service Manual page 91

Check code
[d7]
Protection of low oil level detection
Are balancing pipe valves
of all outdoor units fully open
in the identical line?
YES
Is compressor case oil
removal valve fully open?
YES
Are TK1 and TK2 sensors
correctly connected?
YES
Is there refrigerant stagnation
in compressor case?
Refrigerant
stagnation is
detected.
Modify refrigerant stagnation
in compressor case, reset the
power supply,and then start
the operation.
1. Balancing pipe valve (All outdoor units in the identical line)
closed
2. Compressor case oil removal valve closed
3. Miswiring of TK1 sensor/TK2 sensor
4. Refrigerant stagnation in compressor case
5. SVA3, SV3B, SV3C valves error
6. Blockage in oil return circuit of oil separator
7. Blockage in oil tank circuit
NO
NO
NO
( 1) Is there leakage of
*
NO
2-way valve (SV3A, SV3C) or
blockage (SV3B)?
Leakage/Blockage
( 2) Is there blockage in
*
oil return circuit of oil separator
(Capillary, strainer)?
No blockage
Is there blockage in 2-way
valve of all outdoor units in the
identical line (SV3A, SV3C)?
No blockage
Replace oil tank circuit.
3-88
Operation cause
Open balancing pipe valve fully,
reset power supply, and start
the operation.
Open compressor case oil
removal valve fully, reset
power supply, and start the
operation.
Modify connector connection.
TK1 : CN516
[
TK2 : CN515
YES
Replace defective part.
YES
Replace defective part.
YES
Replace defective part.
]