Haier H-MRV Series - AU48 NFIBIA Troubleshooting; Communication Failure

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AU48NFIBIA troubleshooting:
Reconnect
Reset address
no
yes
1.Communication failure
Is indoor unit address
properly set? Without
repetition?
no
no
no
yes
yes
Are communication terminals of
indoor and outdoor units
securely connected?
Is shielded wire
used for
communication?
Use shielded wire. Shield layer
should be grounded at single
point
Are communication wire
and power cable set
separately?
wiring Separately
yes
yes
yes
Is there external signal
interference?
Eliminate interference
Is indoor mainboard poorly
welded?
no
no
no
yes
Replace indoor PCB
Are communication resistance and
capacitor of indoor PCB correct? See
NOTE
Replace indoor PCB
Check outdoor mainboard. Make
necessary replacement
NOTE: 1. R49.R50 resistor in AS072-182FCBHA circuit and R40.R41 resistor in AE072-242FCBKA
circuit have a resistance of 100 K instead of 47K AS models and C28~C30 of AE models use 104
polyester resistors.
Is number of indoor units
indicated by testing board
correct? Changeable?
yes
yes
Communication normal
Note: For outdoor units before December 2004, in the event of 3 IPM or high current
faults, outdoor unit will stop signal transmission to indoor unit. Indoor unit will display
communication fault.
Normally, testing board will indicate number of indoor units. The number is fixed.
Wired controller display: E9; 4 flashes of indoor TIMER light of models with remote
control
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