Daikin Altherma HT - C9 Indoor Unit: Return Water Thermistor (R4 T)

Troubleshooting by Indication on the Remote Controller ESIE09-08B
142 Troubleshooting
3.9 “C9 ” Indoor Unit: Return Water Thermistor (R4T)
Remote Control
Display
C9
Subcode 0
Applicable
Models
AII indoor unit models
Method of
Malfunction
Detection
Malfunction detection is carried out by temperature detected by return water temperature
thermistor.
Malfunction
Decision
Conditions
When the return water temperature thermistor becomes disconnected or shorted while the unit
is running.
Supposed
Causes
 Defect of indoor unit thermistor (R4T) for water return
 Defect of indoor unit PC board (A1P)
Troubleshooting
 Refer to thermistor resistance / temperature characteristics table on P239.
Caution
Be sure to turn off power switch before connect or disconnect
connector, or parts damage may be occured.
Replace the indoor unit PC board (A1P).
Connect the thermistor and turn
on again.
Faulty thermistor
value > 95C
NO
NO
Replace the thermistor (R4T).
YES
YES
Connector is
connected to X12A of
the indoor unit PC
board.
Resistance
is normal when
measured after
disconnecting the thermistor
(X12A) (R4T) from the
indoor unit PC board.
(7.2k
~112k )
(V2786)
Bad wire connection
value < -43.6C