Au48Nfibia Troubleshooting; Communication Failure - Haier H-MRV Series Service Manual

AU48NFIBIA troubleshooting:

1.Communication failure

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
Is number of indoor units
indicated by testing board
correct? Changeable?
yes
Is indoor unit address
properly set? Without
repetition?
Are communication terminals of
indoor and outdoor units
securely connected?
Is shielded wire
used for
communication?
Are communication wire
and power cable set
separately?
Is there external signal
interference?
Is indoor mainboard poorly
welded?
Are communication resistance and
capacitor of indoor PCB correct? See
NOTE
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.
yes
Communication normal
no
Reset address
yes
no
Reconnect
yes
Use shielded wire. Shield layer
no
should be grounded at single
point
yes
no
wiring Separately
yes
yes
Eliminate interference
no
yes
Replace indoor PCB
no
no
yes
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Replace indoor PCB
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