Troubleshooting for Indoor Unit
Si21-205
156
Troubleshooting
5.12 Transmission Error (Between Indoor and Outdoor Unit)
Remote
Controller
Display
U4
Applicable
Models
FFQ-B, FHQ-BU
Method of
Malfunction
Detection
Microcomputer checks if transmission between indoor and outdoor units is normal.
Malfunction
Decision
Conditions
When transmission is not carried out normally for a certain amount of time
Supposed
Causes
Wiring indoor-outdoor transmission wire is incorrect.
Failure of indoor unit PC board
Failure of outdoor unit PC board
Outside cause (noise, etc.)
Power supply -open phase
Troubleshooting
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.
Is HAP blinking?
NO
NO (ON or OFF)
YES
Is HAP blinking?
Is U4 displayed
normally?
Check for
indoor unit
microcomputer
normal HAP
YES
Turn the power supply off
once and then back on.
Faulty indoor unit PC
board or malfunction of
power supply system
Resets normally.
Could result from
external cause
(e.g. noise).
To outdoor unit PC
board
Replace the indoor unit
PC board.
(S2723)
Measure the voltage between
2 and 3 on terminal board.
(Put minus (-) on 2 with a
multiple meter set to DC
range.)
Is the voltage
10 V or less?
YES
NO
NO
Is the voltage
20 V or more?
NO
YES
To outdoor unit
Caution
Be sure to turn off power switch before connect or disconnect connector,
or parts damage may be occurred.
Summary of Contents for Sky Air B-Series R-410A
Page 7: ...Si21 205 vi Table of Contents ...
Page 15: ...Models Si21 205 4 Model Name and Power Supply ...
Page 16: ...Si21 205 Functions 5 Part 2 Functions 1 List of Functions 6 ...
Page 35: ...Wireless Remote Controller Si21 205 24 Remote Controller ...
Page 79: ...Settings Concerning Maintenance Si21 205 68 Field Setting Detail of PCB 2 ...
Page 83: ...Maintenance Mode Setting Si21 205 72 Field Setting ...
Page 239: ...Troubleshooting for Outdoor Unit 50 60 class Si21 205 228 Troubleshooting ...
Page 321: ...Outdoor Unit 50 60 class Si21 205 310 Removal Procedure ...