Toshiba MMD-AP0724H2UL Service Manual page 68

Check code
Outdoor 7-segment display
Main
remote
controller Check code Sub-code
Detected
outdoor unit
No.
P19 P19
P20 P20 –
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Location
of Description System status
detection
I/F 4-way valve All stop
reversing error
I/F Activation of All stop
high-pressure
protection
– 68 –
Error detection
Check items (locations)
condition(s)
Abnormal refrigerating cycle • Check for defect in main
data is collected during body of 4-way valve.
heating operation. • Check for coil defect in 4-
way valve and loose
connection of its
connector.
• Check resistance
characteristics of TS1 and
TE1 sensors.
• Check output voltage
characteristics of Pd and
Ps pressure sensors.
• Check for wiring error
involving TE1 and TL
sensors.
Pd sensor detects pressure • Check for defect in Pd
equal to or greater than pressure sensor.
522psi(3.6MPa). • Check service valves (gas
side, liquid side) to confirm
full opening.
• Check for defect in outdoor
fan.
• Check for defect in outdoor
fan motor.
• Check outdoor PMVs
(PMV1, 2, 4) for clogging.
• Check indoor/outdoor heat
exchangers for clogging.
• Check for short-circuiting
of outdoor suction/
discharge air flows.
• Check SV2 circuit for
clogging.
• Check for defect in outdoor
P.C. board (I/F).
• Check for defect in indoor
fan system (possible cause
of air flow reduction).
• Check opening status of
indoor PMV.
• Check indoor-outdoor
communication line for
wiring error.
• Check for faulty operation
of check valve in discharge
pipe convergent section.
• Check gas balancing SV4
valve circuit.
• Check SV5 valve circuit.
• Check for refrigerant
overcharging.