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Error Codes: System Malfunctions
ESIE05-03
3–96
Part 3 – Troubleshooting
3
1
3
4
5
4.2
Malfunction of Transmission between Indoor and Outdoor Unit (
U4
or
UF
)
Error code
U4
or
UF
Error generation
The error is generated when the microprocessor detects that the transmission between the indoor and
the outdoor unit is not normal over a certain amount of time.
Causes
The possible causes are:
P
Wiring indoor-outdoor transmission wire is incorrect
P
Malfunctioning indoor unit PCB
P
Malfunctioning outdoor unit PCB
P
Outside cause (noise...).
Troubleshooting 1
Diagnosis of incorrect or broken/disconnected wiring. If the LEDs on the indoor unit PC board are off,
it indicates that the transmission wiring between indoor and outdoor units may be incorrect or
broken/disconnected.
Turn OFF the power supply
once and then ON again.
Measure a voltage between
pins 2 and 3 on the outdoor
unit terminal block.
(Measure this voltage in the
DC range with (–) terminal
connected to 2 and (+)
terminal to 3.)
U4 display is
reproduced.
Is the
Indoor-outdoor
connection wire properly
connected?
Is the
measured voltage
10V or less or 20V
or more?
Proceed to the
following page.
Correct the connection. (Correct
the connection or the type of the
wire.)
External factors (e.g. noises) are
supposed.
Replace the indoor unit PC board.
NO
NO
YES
YES
NO
ESIE05-03.book Page 96 Wednesday, April 6, 2005 4:09 PM
Summary of Contents for RZQ100B7W1B
Page 1: ...Service Manual ESIE05 03 RZQ71 125B8V3B RZQ100 140B7W1B Sky Air Inverter R 410A B series...
Page 2: ......
Page 10: ...ESIE05 03 viii Table of Contents 3 1 4 5...
Page 24: ...ESIE05 03 1 2 Part 1 System Outline 3 1 1 5...
Page 32: ...General Outline Outdoor Units ESIE05 03 1 10 Part 1 System Outline 3 1 1 4 5...
Page 42: ...Specifications ESIE05 03 1 20 Part 1 System Outline 3 1 1 4 5...
Page 56: ...Functional Diagrams ESIE05 03 1 34 Part 1 System Outline 3 1 1 4 5...
Page 58: ...ESIE05 03 1 36 Part 1 System Outline...
Page 70: ...Wiring Diagrams ESIE05 03 1 48 Part 1 System Outline 3 1 1 4 5...
Page 84: ...PCB Layout ESIE05 03 1 62 Part 1 System Outline 3 1 1 4 5...
Page 86: ...ESIE05 03 2 2 Part 2 Functional Description 3 1 2 5...
Page 110: ...General Functionality ESIE05 03 2 26 Part 2 Functional Description 3 1 2 4 5...
Page 150: ...ESIE05 03 3 2 Part 3 Troubleshooting 3 1 3 5...
Page 188: ...Troubleshooting ESIE05 03 3 40 Part 3 Troubleshooting 3 1 3 4 5...
Page 264: ...Additional Checks for Troubleshooting ESIE05 03 3 116 Part 3 Troubleshooting 3 1 3 4 5...
Page 266: ...ESIE05 03 4 2 Part 4 Commissioning and Test Run 3 1 4 5...
Page 306: ...ESIE05 03 5 2 Part 5 Disassembly and Maintenance 3 1 5...