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ESIE06-03
Error Codes: System Malfunctions
3–45
3
3
4
5
1
4.4
“U4”
Signal Transmission Error (between Hydro-box and Outdoor Units)
Error code
U4
Method of
malfunction
detection
The data received from the outdoor unit in hydro-box-outdoor unit signal transmission is checked
whether it is normal.
Malfunction
decision conditions
When the data sent from the outdoor unit cannot be received normally, or when the content of the data
is abnormal.
Supposed causes
P
Faulty outdoor unit PCB.
P
Faulty hydro-box PCB.
P
Hydro-box-outdoor unit signal transmission error due to wiring error.
P
Hydro-box-outdoor unit signal transmission error due to disturbed power supply waveform.
P
Hydro-box
-outdoor unit signal transmission error due to breaking of wire in the connection
wires between the
Hydro-box
and outdoor units.
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 ...