Johnson Controls YVAHP072B31S, Service Manual

Page: 1390 / 1796

3-76
Service Manual
TROUBLESHOOTING
Alarm
Code
Abnormality of Remote Thermistor
(for DOAS)
O
7KH581LQGLFDWRUUHGÀDVKHV
O
The indoor unit number and the alarm code are displayed on the LCD. The alarm code is displayed on
the 7-segment display of the outdoor unit PCB.
+
7KLVDODUPFRGHLVGLVSOD\HGZKHQDVKRUWFLUFXLWNȍRUOHVVRUGLVFRQQHFWLRQNȍRUPRUHRI
the thermistor is detected during a heating, cooling or fan operation.
Yes
Connect them.
No
Refer to "Alarm Code 11"
for thermistor resistance.
Failure of I.U. PCB
Is thermistor THM4
connected to THM4 of
I.U. PCB?
Remote Thermistor
Set “Thermistor for Controller” setting
at Function Setting by Controller.
Thermistor for Controller
Is I.U air temperature detected by
Remote Thermistor (THM4) or
Thermistor for Controller?
Yes
Failure of
Thermistor
No
Is resistance of THM4
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
Failure of
Remote
Thermistor
Replace remote
thermistor if faulty.