Mitsubishi Electric TRANE NTXAMT12A112AA Service Manual page 49

Error Abnormal point and detection method
Code
E7 Indoor/outdoor unit communication error (Transmitting er-
ror)
Abnormal if "1" receiving is detected 30 times continuously
though indoor controller board has transmitted "0".
Fb Indoor controller board
Abnormal if data cannot be read normally from the nonvolatile
memory of the indoor controller board.
E1 Remote controller control board
or
1. Abnormal if data cannot be read normally from the nonvo-
E2
latile memory of the remote controller control board. (Error
code: E1)
2. Abnormal if the clock function of remote controller cannot
be operated normally. (Error code: E2)
PB Fan motor error
Abnormal if a) or b) is detected during fan motor operation.
a) When the number of rotations is detected to be below the
lower limit
for 30 seconds.
b) When the number of rotations is detected to be above the
upper limit
for 30 seconds.
Specifications are subject to change without notice.
NTXAMT12, 18, 24, 30, 36A112AA
Cause
1. Defective transmitting receiv-
ing circuit of indoor controller
board
2. Noise has entered into power
supply
3. Noise has entered into outdoor
control wire
1. Defective indoor controller
board
1. Defective remote controller
1. Motor or fan cannot rotate be-
cause of foreign object, etc.
2. Motor wire disconnection or
connector disconnection or
looseness
3. Motor failure
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Countermeasure
1~3. Turn the power off, and on again to
check. If abnormality generates again, replace
indoor controller board.
1. Replace indoor controller board.
1. Replace indoor controller board.
1. Remove the foreign object causing the
problem.
2. Check disconnection of the motor wiring
or connector disconnection.
3. Replace the failed motor.