Hitachi RAS-25JX4 Service Manual page 95

6. Failure Phenomenon: Two way air exchange lamp blinks
<Situation> Two way air exchange lamp blinks (lit for 4 seconds and off for 1 second).
Dirt sensor is not functioning.
ÒTimer lamp blinks 17 timesÓ is not stored in the self-diagnosis memory.
<Assumed points of failure>
<Caution> Self-diagnosis (failure detection) of dirt sensor is performed at the time when automatic two way air exchange is
set.
<Diagnosis flow>
roubleshooting start
Is the connector (CN9) of the dirt sensor board inserted
securely? Is there wiring disconnection?
Replace Òdirt sensor boardÓ.
Incomplete insertion of the connector of dirt sensor board
Dirt sensor
Yes
No
100
Repair connector or wiring.