Midea V8 VRF Series Service Manual page 55

V8 VRF Indoor Units
6.1.12 b12, b14 - Error in 1# electronic expansion valve body, error in 2# electronic expansion valve body
Error display
The faulty IDU and other IDUs of the same system: operate normally.
Error impact
ODU of the same system: operate normally.

Error trigger

Error recovery
Automatic recovery


Possible cause

Troubleshooting
Note:
1. The error code corresponds to the following two situations:
1) If there is only one electronic expansion valve port on the main control board of the IDU, when
an internal leakage error occurs in the electronic expansion valve body connected to the EXV port,
the error code is b12.
2) If there are two electronic expansion valve ports on the main control board of the IDU named
EXV1 and EXV2, when there is a leak inside the electronic expansion val ve body connected to
port EXV1, the error code is b12; when there is a leak inside the electronic expansion valve body
connected to port EXV2, the error code is b14.
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Digital display
Return air temperature(T1) - Heat exchanger liquid pipe temperature (T2A) > Set value
IDU EXV=0, ODU running in cooling mode and compressor speed ≠0
The electronic expansion valve needle is stuck or clogged.
The electronic expansion valve coil is damaged and unable to drive the valve body.
The IDU main control board is damaged.
b12/b14 (1)
Remove
the coil and fix it to the valve
body again. Is the fault
cleared?
No
Replace
the coil and
re-energize. Is the error
cleared?
No
Replace
the main control board
Is the fault
cleared?
No
Replace the electronic
expansion valve body (the
interior of the body is
clogged or the valve needle
is stuck)
Display position
Panel or display box
Spot check interface query
Yes
Operate normally (loose coil)
Yes
Operate normally (the coil
cannot drive the valve body)
Operate normally (the IDU
main control board is
Yes
damaged and the electronic
expansion valve body
cannot be driven)
Wired controller
Error code is not
displayed