Midea ATOM B Series Service Manual page 63

Atom B Series VRF 50/60Hz
2.14 H4: L (L0/L1) fault occurs three times in one hour (For all models)
2.14.1 Digital display output
H4
2.14.2 Description
 The L (L0/L1) fault occurs three times in one hour.
 The system stops running.
 Error code is displayed on the unit with the error.
2.14.3 Trigger / recover condition
 Trigger condition: The L (L0/L1) fault occurs three times in one hour.
 Recover condition:DC bus voltage goes back to normal.
 Reset method: Resume automatically.
2.14.4 Possible causes
 DC bus voltage is too low.
 IPM Module has short circuit.
 Fan motor short circuit.
 Outdoor unit main control board damaged.
2.14.5 Procedure
Check the DC bus voltage whether too
Inspect module has short circuit or not
Inspect Fan motor has short circuit or not
Outdoor unit main control board
62
H4
low or not
No
No
No
damaged
Yes
DC bus voltage is too low
Yes
Replace a new module
Yes
Replace a new fan motor