Johnson Controls YVAHP072B31S, Service Manual

Page: 1386 / 1796

3-72
Service Manual
TROUBLESHOOTING
Alarm
Code
Abnormality of Thermistor for Indoor Unit Outlet Air Temperature
(Outlet Air Thermistor)
O
7KH581LQGLFDWRUUHGÀDVKHV
O
The indoor unit number (refrigerant cycle number - address number), the alarm code, the model code*
1)
,
the model name*
1)
and the number of connected indoor units are displayed on the LCD. The indoor unit
number and the alarm code are displayed on the 7-segment display of the outdoor unit PCB.
*1) Except for some models.
+
7KLVDODUPFRGHLVGLVSOD\HGZKHQDVKRUWFLUFXLWNȍRUOHVVRUGLVFRQQHFWLRQNȍRUPRUHRI
the thermistor is detected during a heating or cooling operation. The operation automatically restarts
when the malfunction is removed.
Yes
Connect them.
No
Refer to "Alarm Code 11"
for thermistor resistance.
Failure of I.U. PCB
Is thermistor THM2 (for
outlet air temp.) connected
to THM2 of I.U. PCB?
Yes
Failure of
Thermistor
No
Is resistance of THM2
between 0.24k
Ω
and
840k
Ω
?
Cause Check Item
Action
(Turn OFF Main Switch)
Event
Failure of
Outlet Air
Thermistor
Check resistance.
Replace thermistor
if faulty.
Failure
Check wiring to
I.U. PCB.
Correctly connect wires.
Incorrect Connection
Replace I.U. PCB
and check operation. Replace I.U. PCB
if faulty.
Failure of I.U. PCB
Outlet Air Thermistor
Example of 4-way Cassette Type