Midea ATOM B Series Service Manual page 64

2.15 H7: The number of online indoor units have decreased/increased (For all models)
2.15.1 Digital display output
H7
2.15.2 Description
 The number of online indoor units have decreased/increased.
 The system stops running.
 Error code is displayed on the unit with the error.
2.15.3 Trigger / recover condition
 Trigger condition: The number of online indoor units have decreased/increased.
 Recover condition: Number of indoor units detected is the same as first power on.
 Reset method: Resume automatically.
2.15.4 Possible causes
 Communication wire or power supply wire connection problem.
 Indoor unit main control board damaged.
 Outdoor unit main control board damaged.
2.15.5 Procedure
Waiting for 3 minutes to check whether
the fault would resume
Inspect whether indoor unit address
repeat, clear and reset indoor unit's
address to check whether fault cleared
Inspect communication wire and power
supply wire whether exist loose or poor
connection problem
Power off outdoor unit and all indoor
units, and the repower on, turn on part
of indoor units to check whether outdoor
unit operate normally
Outdoor unit main control board is fault
H7
No
No
No
No
Atom B Series VRF 50/60Hz
There are some indoor units power off or
Yes
power on in the operation period
Yes
Indoor unit address repeat
Yes Connection wire installation problem
Yes
Indoor unit main control board is fault
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