Mitsubishi Heavy Industries FDUA160AVSAVH Service Manual page 119

Troubleshooting
Symptoms
∙No air flow
∙  I f there is no common zone,
ensure that spill zone is set.
Poor air flow
Assumed Causes
Faulty damper motor
Relay and damper motor
incorrectly wired.
Fuse blown
For 24V AC damper motor,
transformer is not connected and
the voltage is incorrect.
External static pressure is not
correct.
If duct static pressure is too
high, indoor unit will go into frost
prevention mode.
Over 4 zones
Zone settings is not correct.
-
Replace damper motor.
Check wiring, ensure zone opens and closes
correctly.
Investigate cause and replace blown fuse.
Check 24V AC transformer.
Ensure that air flow of common zone or spill zone
equal 50% of total air flow.
Ensure that ducts other than common zone or spill
zone have equal static pressure(equal air flow).
Ensure that it is 4 zones or less including the
common zone(spill zone).
If there is no common zone, ensure that spill zone
is set.
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Solutions