Toshiba MMD-AP0071SH-C Service Manual page 92

Check code name Check code name
[H04] / [44] Compressor 1 case thermo operation
(d07 / AI-NET)
[H14] / [44] Compressor 2 case thermo operation
(d07 / AI-NET)
Is case thermo circuit normal?
NO
1. Connector connection
2. Wiring
(Note 1)
3. I/F P.C. board (Note 1)
1. Case thermo is usually closed.
2. Operation temperature of case thermo is 120˚C.
YES
Are service valves of NO
gas pipe and liquid pipe of
outdoor unit fully opened?
YES
Are outdoor PMV1/2/3 normal?
NO
1. Connector connection
2. Wiring 3. Coil
Connector CN300, 301, White
4. Valve body 5. I/F P.C. board
YES
Operation starts.
Are SV41 and SV42
Valve circuits normal?
NO
1. Misinstallation installation and
connector connection of SV41
SV4 valve: Connector CN311, Blue
and SV42
2. Leakage from SV41, 42 circuit
YES
Does not refrigerant
YES
bypass from discharge of
suction through 4-way valve?
NO
YES
Is not refrigerant bypassed
from discharge to suction?
NO
NO
Is compressor normal? (Note 2)
(Note 2) Check the following items mainly.
YES
1. Existence of abnormal sound and abnormal vibration during operation at start time
2. Abnormal overheat of case during operation or stop (Never touch with hands.)
3. Current of compressor lead during operation or starting (No rapid current change)
YES
Is flow selector unit normal?
NO
Refrigerant shortage,
(After checking there is no slogging or pipe breakage, charge refrigerant again.)
clogging, pipe breakage
Cause of operation
1. Case thermo circuit error
2. I/F P.C. board error
3. Service valve closed
4. Outdoor PMV clogging
5. SV4 valve leak, Coil misinstallation
6. 4-way valve error
7. Compressor error
8. Refrigerant shortage
Repair case thermo circuit.
Open service valves fully.
Repair outdoor PMV.
Correct SV4, SV5, SV11
valve circuits.
Check 4-way valve.
Check piping.
Compressor error
Check flow selector unit.
Check code name Check code name
[H06] / [20] Low-pressure protective operation
(d07 / AI-NET)
NO
Are service valves of gas and
liquid pipe of outdoor unit fully opened?
YES
NO
Are characteristics of low-pressure sensor normal?
1 Pressure by pressure gauge (Check joint)
YES 2 Pressure display on 7-segment display
3 Output voltage of I/F P.C. board
NO
Are SV2 and SV4 circuits normal?
Check miscabling, misinstallation and
YES connector connection.
YES
Is there no mispiping of discharge gas
and suction gas main pipes?
NO
YES
Is not indoor unit with different circuit connected?
NO
NO
Is flow selector normal?
YES
(A) Cooling
NO
Does indoor fan normally
operate in cooling season?
YES
YES
Is there clogging of indoor
Cleaning
air filter or heat exchanger?
NO
NO
Is indoor PMV normal?
YES
Refrigerant shortage or
clogging or pipe deformed
(B) Heating
NO
Is outdoor fan normally
operated in heating season?
YES
YES
Is there clogging of
Cleaning
outdoor heat exchanger?
NO
NO
Is outdoor PMV normal?
YES
Cause of operation
1. Service valve close
2. Ps sensor error
3. SV2, SV4 circuit error
4. Miscabling of communication between
indoor and outdoor
5. Indoor/outdoor fan and condenser error
6. Indoor/outdoor PMV clogging
7. Indoor/outdoor heat exchanger clogging
8. Refrigerant shortage
Open service valves fully.
Exchange low-pressure sensor.
If 1 and 2, 3 are different, an error of pressure sensor error is considered.
If 2 and 3 are different, check I/F P.C. board.
Correct SV2 and SV4 circuits.
Correct piping.
Correct cabling.
(Check with miscabling check
function of outdoor unit.)
Check flow selector.
In cooling season, go to (A), In heating season, go to (B)
Are following items concerned
to indoor fan motor normal?
NO
1. Connector connection
Repair faulty parts.
2. Condenser
3. Motor
4. Fan
YES
Check indoor P.C. board.
Failure
NO
Is connector connection
Repair faulty parts.
or coil normal?
YES
YES
Is there clogging on whole valve? Replace PMV body.
NO
Is indoor fan system normal? NO Check outdoor
I/F P.C. board.
• Fan crack
• Fan coming-off Failure
YES
Repair faulty parts.
Refrigerant shortage,
clogging, pipe deformed
Replace
Replace