Toshiba MMU-AP0072H2UL Service Manual page 100

Check code
Outdoor 7-segment display
Main
remote
Check code
controller
Detected
outdoor unit
No.
P19 P19
P20 P20
Location
of Description
detection
Sub-code
I/F 4-way valve
reversing error
I/F Activation of
high-pressure
protection
–
Error detection
System status
condition(s)
All stop Abnormal refrigerating cycle
data is collected during
heating operation.
All stop Pd sensor detects pressure
equal to or greater than
522psi(3.6MPa).
100
Check items (locations)
• Check for defect in main
body of 4-way valve.
• 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.
• Check for defect in Pd
pressure sensor.
• 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.