Toshiba SUPER MMK-AP0073H (IN) Service Manual page 122

Check code
[P20] / [22]
(Current code / AI-NET)
Are service valves fully opened?
YES
Are characteristics of
high-pressure sensor normal?
YES
Reset power supply, and start a test
operation corresponded to the season.
B Cooling operation
Does cooling outdoor fan
normally operate?
YES
Is there no fan crack or coming-off?
NO
Is outdoor PMV normal?
YES
Is there a cause to interfere operation
of heat exchanger of outdoor unit?
1. Heat exchanger clogging
2. Air short circuit
NO
Is SV2 circuit normal?
YES
Is SV4 circuit normal?
YES
Does check valve of main
discharge pipe normally operate?
YES
Refrigerant overcharge, clogging,
pipe breakage, abnormal overload condition
Check code name
High-pressure
protective operation
NO
NO
Cooling → To B
Heating → To C
* 1. Pressure by pressure gauge (Check joint)
2. Pressure display on 7-segment display
3. Output voltage of I/F P.C. board
If 1 and 2, 3 are different, an error of pressure sensor is considered.
If 2 and 3 are different, check I/F P.C. board.
NO
YES
NO
YES
NO
NO
NO
Cause of operation
1. Pd sensor error
2. Service valve closed.
3. Indoor/outdoor fan error
4. Indoor/outdoor PMV clogging
5. Indoor/outdoor heat exchanger clogging
6. SV2 circuit error
7. SV4 circuit error
8. SV5 circuit error
9. Outdoor I/F P.C. board error
10. Operation error of check valve of main discharge pipe
11. Refrigerant overcharge
(Connector connection, fan IPDU, fan motor, cabling)
(Connector connection wiring, coil mounting, valve clogging, etc)
(Coil error, clogging, disconnection of cable, etc.)
(Coil error, clogging, disconnection of cable, etc.)
122
Open service valves fully.
Check parts.
Failure → Replace
Correct faulty parts.
Correct faulty parts.
Correct faulty position.
Eliminate the interfered causes.
Repair SV2 circuit.
Repair SV4 circuit.
Repair check valve. → Replace