Troubleshooting for SkyAir Indoor Unit SiAU18-715
342 Troubleshooting
5.9 Malfunction of Heat Exchanger Thermistor (R3T)
Remote
Controller
Display
C5
Applicable
Models
FFQ, FCQ, FBQ, FHQ
Method of
Malfunction
Detection
Malfunction detection is carried out by temperature detected by heat exchanger sensor (R3T).
Malfunction
Decision
Conditions
When the heat exchanger thermistor becomes disconnected or shorted while the unit is running.
Supposed
Causes
Failure of the sensor itself
Broken or disconnected wire
Failure of electronic circuitry (indoor unit PCB)
Failure of connector contact
Troubleshooting
Check No.02
Refer to P.349
Connect correctly.
Heat exchanger
sensor replacement.
If contact is OK,
replace indoor unit
PCB.
NO
NO
YES
YES
(Q0539)
Disconnect the heat exchanger
sensor (R3T) from X17A on
the indoor unit PCB and
measure the resistance.
Is the
thermistor normal?
(See note)
Is it normal?
Check contact of connector
+See Check No. 02 for “Thermistor temperature and resistance characteristics”.
Caution
Be sure to turn off power switch before connect or disconnect connector,
or parts damage may be occurred.