128
Check code
Location
of
detection
Description System status Error detection condition(s) Check items (locations)
Wired
remote
control
Outdoor 7-segment display
Check
code
Sub-code
P18 P18 –
I/F Discharge
temperature
TD3 error
All stop Discharge temperature (TD3)
exceeds 239 °F (115 °C).
• Check outdoor service valves
(gas side, liquid side) to confirm
full opening.
• Check outdoor PMVs (PMV1, 2,
4) for clogging.
• Check resistance characteristics
of TD3 sensor.
• Check for defect in 4-way valve.
• Check SV43 circuit for leakage.
• Check SV4 circuit (for wiring or
installation error involving SV41,
SV42 and SV43).
P19 P19
Detected
outdoor unit
No.
I/F 4-way valve
reversing error
All stop Abnormal refrigerating cycle data is
collected during heating operation.
• 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.
P20 P20 –
I/F Activation of
high-pressure
protection
All stop Pd sensor detects pressure equal to
or greater than 522 psi (3.6 MPa).
• 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.
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