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Crypton
07-07-2011, 10:09 AM
Hi I have an LG Multi split. Model FM30AH. System working fine then went down. When i turn on system now indoors run for maybe 2min, outdoor doest try to start. Then led on face plate starts flashing red 5 times and indoor unit fan stops spinning. Communication problem is very vauge can anyone else through light on it.

install monkey
07-07-2011, 07:18 PM
Fault Code 05 and 53 (CH05 is displayed at indoor unit, 53 is displayed at outdoor unit)

This fault code indicates a communication error between the indoor and outdoor units; this is usually caused
by wiring errors or condensate pumps connected to the inter-connecting cable.

The communication between the units is a fluctuating DC voltage commonly called a serial signal, it can be

easily lost if the wiring is not done correctly. If there is a communication error fault

CH05 will appear within 5

mins of powering up the systemTesting
Check Outdoor and Indoor Power Supply Voltages ( 230V ±10% ) and correct as necessary.



Check for any mis-wiring or loose connections and correct as required.



Check the resistance between communication line and GND. (Normal: Over 2M).



If one Indoor unit operates normally Outdoor PCB is generally normal.

Turn on the power and start the indoor unit in cooling, set the temperature to 18șC; the serial communication

signal will only be present for the first 3 mins of operation.

Set your meter to DC Volts, Test between terminals 5 (Red probe) and 2 or Earth (Black probe) of the outdoor

unit, you should see a fluctuating 0-72 Vdc.

If the Voltage is not present disconnect the terminal 5 cable, test the Voltage between this wire (Red probe)

and 2 or Earth (Black probe), you should see a steady voltage in the range of -0.1 to -10.0 Vdc. If No Voltage

is present either the cable or Indoor PCB must be faulty. This can be determined by checking the voltage

output on the Comms terminal of the Indoor unit, with the Comms wire disconnected. If No Voltage is present

the Indoor PCB must be faulty, if present, cable must be at fault.

Crypton
08-07-2011, 09:30 AM
That is a perfect answer, fair play to you mate. That's exactly what I was looking for. Ill print this off and go checking it out. Thanks again.