Daikin RTSQ20PY1 Service Manual page 362

Troubleshooting (Heat Reclaim Ventilation)
CHECK 14
List of inverter-related malfunction codes
Code
L5 Instantaneous overcurrent of
inverter compressor
L8 Overcurrent of inverter
compressor (Electronic thermal)
L1 Faulty inverter PCB
L9 Faulty startup of inverter
compressor
E5 Inverter compressor lock
L4 Radiator fin temperature rise
U2 Power supply voltage error
P1 Imbalanced power supply
LC Transmission error (between
inverter PCB and control PCB)
PJ PCB mismatching
P4 Faulty fin thermistor
351
Name Condition for determining malfunction
• Inverter output current exceeds 32.3A even
instantaneously.
• Compressor overload running
An overcurrent of 19.0A or more continues for
a period of 5 consecutive seconds or that of
16.1A or more continues for a period of 260
consecutive seconds.
• The inverter loses synchronization.
• No output is given.
• The compressor motor fails to start up.
• The compressor is in the locked status (does
not rotate).
• The radiator fin temperature reaches 93°C or
more (while in operation).
• The inverter power supply voltage is high or
low.
• Power supply voltages get significantly
imbalanced among three phases.
• With the outdoor unit PCB, no
communications are carried out across control
PCB - inverter PCB - fan PCB.
• Any PCB of specification different from that of
the product is connected.
• The fin thermistor gets short-circuited or open. • Faulty fin thermistor
SiBE31-801_C
Major cause
• Liquid sealing
• Faulty compressor
• Faulty inverter PCB
• Backflow of compressor liquid
• Sudden changes in loads
• Disconnected compressor wiring
• Faulty inverter PCB
• Faulty heavy current part of
compressor
• Liquid sealing or faulty
compressor
• Excessive oil or refrigerant
• Faulty inverter PCB
• Faulty compressor
• Malfunction of fan
• Running in overload for an
extended period of time
• Faulty inverter PCB
• Power supply error
• Faulty inverter PCB
• Power supply error (imbalanced
voltages of 2% or more)
• Faulty inverter PCB
• Dead inverter PCB
• Broken wire in communication
line
• Faulty control PCB
• Faulty inverter PCB
• Faulty fan PCB
• PCB of different specification
mounted
Troubleshooting