Johnson Controls YVAHP0721CW Series, Service Manual

Page: 225 / 416

SM-16007
3-61
TROUBLESHOOTING
Alarm
Code
Abnormality of Thermistor for Gas Refrigerant Pipe Temperature
at Indoor Unit Heat Exchanger (Gas Pipe 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.
Refer to "Alarm Code 11"
for thermistor resistance.
Yes
Yes
Connect them.
No
Failure of
Thermistor
Failure of I.U. PCB
No
Is thermistor THM5
(for gas pipe) connected
to THM5 of I.U. PCB?
Is resistance of THM5
between 0.24k
Ω
and
840k
Ω
?
Cause Check Item
Action
(Turn OFF Main Switch)
Event
Failure of
Thermistor
for Indoor Unit
Heat Exchanger
Gas Pipe Temp.
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
Gas Pipe Thermistor
*1): The heating operation is available only during the test run.
Example of 4-way Cassette Type