Daikin GYEQ20AN, Руководство по обслуживанию

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Flow Charts for Troubleshooting SiAUY361411EA
167 Troubleshooting
43
Outdoor/Indoor Unit Transmission Failure
Error
code
U4
Description
of the failure
Sub-code 0: The outdoor and indoor units are unable to communicate with each other within 50 seconds after
power-ON or unable to communicate with each other within 3 minutes after they are connected
over the communication link (which means that all the indoor units have a transmission failure).
Possible
causes
of the failure
DIP switches misconfigured; indoor unit power supply not turned ON; fuse failure;
communication line connection failure; communication line incorrectly installed
Flow chart
YES
NO
YES
NO
YES
NO
YES
NO
Are Outdoor Units
Powered ON?
Check And
Turn ON
Power Supply.
Does Earth Leakage
Breaker (ELB) In Outdoor
Unit Remain Inactive?
Check And
Repair
Earth Leakage.
Check
Starter System.
Are Fuses On Outdoor
Unit Circuit Boards
Non-Defective?
Check Fuses.
Is the indoor unit and
BS unit power turned on
Check And
Turn ON
Power Supply.
YES
NO
YES
NO
YES
NO
Are the outdoor unit-indoor
unit, and indoor unit-BS unit
communications cables
disconnected?
Check
Communication
Cables.
Are You Sure Terminals
On Terminal Block Are
Not Loosened?
Retighten
Terminals.
Are You Sure
Communication Signal
Waveform Is Not
Distorted?
Correct Wiring.
Power Supply System Communication System
025911-01EN01
Check fuses on
circuit board.
Check whether
Transmission
Usage is not too
much.