Midea ATOM B Series Service Manual page 78

2.21 P9: Poor reversing of four-way valve (For all models)
2.21.1 Digital display output
P9
2.21.2 Description
 P9 indicates poor reversing of four-way valve.
 The system stops running.
 Error code is displayed on the outdoor unit PCB.
2.21.3 Trigger / recover condition
 Trigger condition: Poor reversing of four-way valve.
 Recover condition: Four-way valve recover to normal .
 Reset method: Resume automatically.
2.21.4 Possible causes
 Four-way valve is damaged.
 Main PCB damaged.
2.21.5 Procedure
P8
Whether the four-way valve wires
connect good or not
No
Main PCB damaged
Atom B Series VRF 50/60Hz
Connect the four way
Yes
valve wires with the
port correctly
77