Toshiba MMU-UP0051MH-E(TR) Service Manual page 114

Check code
Main Outdoor 7-segment display
remote
Check
Sub-code
controller
code
P17 P17 —
Detected
outdoor unit No.
P19 P19
P20 P20 —
Location
Description
of
detection
I/F Discharge
temperature
TD2 trouble
I/F 4-way valve
reversing
trouble
I/F Activation of
high-pressure
protection
Check code detection
System status
condition(s)
All stop Discharge temperature
(TD2) exceeds 115 ˚C.
All stop Abnormal refrigerating cycle
data is collected during
heating operation.
All stop <During cooling operation>
Pd sensor detects pressure
equal to or greater than
3.85 MPa.
<During heating operation>
Pd sensor detects pressure
equal to or greater than
3.6 MPa.
– 114 –
Check items (locations)
• Check outdoor service
valves (gas side, liquid
side) to confirm full
opening.
• Check outdoor PMVs
(PMV1, 2, 3, 4) for
clogging.
• Check resistance
characteristics of TD2
sensor.
• Check for failure in 4-way
valve.
• Check SV4 circuit for
leakage.
• Check SV4 circuit (for
wiring or installation trouble
involving SV41 and SV42).
• Check for failure in main
body of 4-way valve.
• Check for coil failure in 4-
way valve and loose
connection of its connector.
• Check resistance
characteristics of TS1 and
TE1,TE2 sensors.
• Check output voltage
characteristics of Pd and
Ps pressure sensors.
• Check for wiring trouble
involving TE1 and TL1
sensors.
• Check for failure in Pd
pressure sensor.
• Check service valves (gas
side, liquid side) to confirm
full opening.
• Check for failure in outdoor
fan.
• Check for failure in outdoor
fan motor.
• Check outdoor PMV
(PMV1, 2, 3, 4) for
clogging.
• Check indoor/outdoor heat
exchangers for clogging.
• Check for short-circuiting
of outdoor suction/
discharge air flows.
• Check for failure in outdoor
P.C. board (I/F).
• Check for failure in indoor
fan system (possible cause
of air flow reduction).
• Check opening status of
indoor PMV.
• Check indoor-outdoor
communication line for
wiring trouble.
• Check for troble operation
of check valve in discharge
pipe convergent section.
• Check gas balancing SV4
valve circuit.
• Check for refrigerant
overcharging.