Transmission Error (Between Indoor And Outdoor Unit) - Daikin Sky Air B-Series R-410A Service Manual

Troubleshooting for Indoor Unit

5.12 Transmission Error (Between Indoor and Outdoor Unit)

U4
Remote
Controller
Display
Applicable
FFQ-B, FHQ-BU
Models
Method of Microcomputer checks if transmission between indoor and outdoor units is normal.
Malfunction
Detection
Malfunction
When transmission is not carried out normally for a certain amount of time
Decision
Conditions
Supposed
Causes
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.
156
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
Be sure to turn off power switch before connect or disconnect connector,
Caution or parts damage may be occurred.
Is HAP blinking?
Check for
indoor unit
microcomputer
normal HAP
Is U4 displayed
normally?
YES
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?
NO
Is the voltage
20 V or more?
YES
To outdoor unit
NO (ON or OFF)
Turn the power supply off
once and then back on.
Is HAP blinking?
YES
NO
YES
NO
Si21-205
NO
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)
Troubleshooting