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Error Codes: System Malfunctions
ESIE06-03
3–44
3
1
3
4
5
4.3
“U2”
Low-voltage Detection or Over-voltage Detection
Error code
U2
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
P
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.
P
The system will be shut down if the error occurs 16 times.
P
Clearing condition: Continuous run for about 60 minutes (normal)
Supposed causes
P
Supply voltage not as specified
P
Over-voltage detector or DC voltage detection circuit defective
P
PAM control part(s) defective
Troubleshooting
Caution
Be sure to turn off power switch before connect or disconnect connector, or parts damage may be
occurred.
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.)
NO
YES
NO
Repeat a
couple of times.
Supply voltage as
specified?
Turn
on the power again.
System restarted?
YES
Check the supply voltage.
Disturbance factors
∗
Noise
∗
Power supply distortion
(Precaution before turning on the power again)
Make sure the power has been off for at least
30 seconds.
Summary of Contents for Altherma EKHBH Series
Page 2: ...ESIE06 03 1 2 Part 1 System Outline 3 1 1 5 ...
Page 26: ...Functional Diagrams ESIE06 03 1 26 Part 1 System Outline 3 1 1 4 5 ...
Page 32: ...Piping Diagrams ESIE06 03 1 32 Part 1 System Outline 3 1 1 4 5 ...
Page 38: ...Switch Box Layout ESIE06 03 1 38 Part 1 System Outline 3 1 1 4 5 ...
Page 58: ...PCB Layout ESIE06 03 1 58 Part 1 System Outline 3 1 1 4 5 ...
Page 60: ...ESIE06 03 2 2 Part 2 Functional Description 3 1 2 5 ...
Page 68: ...Hydro box Functional Concept ESIE06 03 2 10 Part 2 Functional Description 3 1 2 4 5 ...
Page 88: ...ESIE06 03 3 2 Part 3 Troubleshooting 3 1 3 5 ...
Page 134: ...Error Codes System Malfunctions ESIE06 03 3 48 Part 3 Troubleshooting 3 1 3 4 5 ...
Page 152: ...Additional Checks for Troubleshooting ESIE06 03 3 66 Part 3 Troubleshooting 3 1 3 4 5 ...
Page 154: ...ESIE06 03 5 2 Part 5 Disassembly and Maintenance 3 1 5 ...