Daikin VRV RXYQ72-384XAYCA, Service Manual

Page: 257 / 419

SiUS342004EB Troubleshooting by Error Code
Part 6 Service Diagnosis 250
Reference
3.15 Electronic Expansion Valve Coil Abnormality, Dust
Clogging
Applicable
Models
All indoor unit models
Error Code
A9
Method of Error
Detection
Check coil condition of electronic expansion valve by using microcomputer.
Check dust clogging condition of electronic expansion valve main body by using microcomputer.
Error Decision
Conditions
Pin input for electronic expansion valve coil is abnormal when initializing microcomputer.
Either of the following conditions is seen/caused/occurs while the unit stops operation.

R1T – R2T > 8°C (14.4°F)

R2T shows fixed degrees or below.
R1T: temperature of suction air
R2T: temperature of liquid pipe of heat exchanger
Supposed
Causes

Defective electronic expansion valve coil

Defective indoor unit control PCB

Defective relay cables
Troubleshooting
CHECK 18 Refer to page 376.
NO
YES
Error
code is displayed
when power is supplied
to the indoor
unit?
NO
Electronic
expansion valve is
connected to X7A of
indoor unit control
PCB.
NO
Check
of electronic
expansion valve coil
indicates normal.
NO
YES
YES
YES
Relay
cables short circuit or
disconnected.
When restarting the operation
after shutting the power supply
OFF does not work, replace the
indoor unit control PCB (A1P).
Replace the relay cables.
Replace the electronic
expansion valve coil (Y1E).
Shut the power supply OFF
after connection and then
restart.
Replace the electronic
expansion valve main body.
CHECK 18
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.