Specifications
Table Of Contents
- Cover
- Table of Contents
- Part 1 List of Functions
- Part 2 Specifications
- Part 3 Printed Circuit Board Connector Wiring Diagram
- Part 4 Function and Control
- Part 5 Operation Manual
- Part 6 Service Diagnosis
- 1. Caution for Diagnosis
- 2. Problem Symptoms and Measures
- 3. Service Check Function
- 4. Code Indication on the Remote Controller
- 5. Troubleshooting
- 5.1 Indoor Units
- 5.2 Outdoor Units
- 5.3 Indoor Unit PCB Abnormality A1
- 5.4 Freeze-up Protection Control or High Pressure Control A5
- 5.5 Fan Motor or Related Abnormality A6
- 5.6 Thermistor or Related Abnormality (Indoor Unit) C4,C9
- 5.7 Front Panel Open / Close Fault C7
- 5.8 Signal Transmission Error (between Indoor and OutdoorUnit) U4
- 5.9 Unspecified Voltage (between Indoor and Outdoor Units) UA
- 5.10 Freeze-up Protection Control A5
- 5.11 Outdoor Unit PCB Abnormality E1
- 5.12 OL Activation (Compressor Overload) E5
- 5.13 Compressor Lock E6
- 5.14 DC Fan Lock E7
- 5.15 Input Over Current Detection E8
- 5.16 Discharge Pipe Temperature Control F3
- 5.17 High Pressure Control in Cooling F6
- 5.18 Compressor Sensor System Abnormality H0
- 5.19 Position Sensor Abnormality H6
- 5.20 CT or Related Abnormality H8
- 5.21 Thermistor or Related Abnormality (Outdoor Unit) P4,J3,J6,J8,J9,H9
- 5.22 Electrical Box Temperature Rise L3
- 5.23 Radiation Fin Temperature Rise L4
- 5.24 Output Over Current Detection L5
- 5.25 Insufficient Gas U0
- 5.26 Low-voltage Detection or Over-voltage Detection U2
- 5.27 Signal Transmission Error (on Outdoor Unit PCB) U7
- 5.28 Anti-icing Function in Other Rooms / UnspecifiedVoltage (between Indoor and Outdoor Units) UA,UH
- 6. Check
- Part 7 Removal Procedure
- Part 8 Others
- Part 9 Appendix
- Index
- Drawings & Flow Charts

SiBE12-713 Troubleshooting
Service Diagnosis 273
5.26 Low-voltage Detection or Over-voltage Detection
Remote
Controller
Display
U2
Outdoor Unit LED
Display
A
5
1
4
2
1
3
1
4
4
Method of
Malfunction
Detection
An abnormal voltage rise or drop is detected by checking the detection circuit or DC voltage
detection circuit.
Malfunction
Decision
Conditions
An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer, or
the voltage being detected by the DC voltage detection circuit is judged to be below 150 V
for 0.1 second.
The system will be shut down if the error occurs 16 times.
Clearing condition: Continuous run for about 60 minutes (normal)
Supposed
Causes
Supply voltage not as specified
Over-voltage detector or DC voltage detection circuit defective
PAM control part(s) defective
Troubleshooting
Check the supply voltage.
Correct the power supply.
Check for such factors for a
long term.
∗ Try to get restarted a
couple of times.
Replace the PM1.
(Replace the outdoor unit
PCB.)
(R5151)
Caution
Be sure to turn off power switch before connect or disconnect connector,
or parts damage may be occurred.
Supply voltage as
specified?
NO
YES
Turn on the
power again.
System restarted?
NO
Repeat a
couple of times.
YES
(Precaution before turning on the power again)
Make sure the power has been off for
at least 30 seconds.
Disturbance factors
∗ Noise ∗ Power supply distortion