Lg Multi Fault Codes

LG Air Conditioning Multi F(DX) Fault Codes Sheet

Multi Split Units

If there is a fault on any LG Multi unit, an Error mark is indicated on the display window of the indoor unit, wired-remote controller, and LED’s of outdoor unit control board.

A two digit number will appear on the wired remote controllers LCD display, e.g. CH05. If the unit does not have a wired remote the fault will be displayed using the LED's on the front of the indoor unit.

If more than two troubles occur simultaneously, the lower numbered error code is displayed first.

After an error occurs, if error is released, error LED is also released simultaneously.

Error Indicator:

Off

Off

Off

Off

Off

On

On

On

Indoor Unit Faults:

Error

Display

Fascia LED’s

Red Green

CH01 or C1 None

CH02 or C2 None

CH03 or C3 None

CH04 or C4 None

CH05 or C5 None

CH06 or C6 None

Contents

1 Flash

2 Flash

3 Flash

4 Flash

5 Flash

6 Flash

Indoor Air Sensor

(Open/Short)

Inlet Pipe Sensor

Communication (Indoor ↔

Wired R/Control)

Drain Pump / Float Switch

Communication Error (Indoor

↔ Outdoor)

Outlet Pipe Sensor

CH07 or C7 None

CH09 or C9 None

CH10 or CA 1 Flash

HL

CL

Po

Lo

-

-

-

-

7 Flash

9 Flash

None

-

-

-

-

Different Operation Mode

EEPROM Check Sum

BLDC Fan Motor Lock

High Limit (Float Switch) or

Hard Lock

Child Lock Function Selected

Jet Cool Mode Selected

System in Test Mode

Case of Error

Open or Short Circuit


Data Communication Fault

Float Switch Open Circuit (High

Level Water Alarm)

Data Communication Fault


Indoor Unit is Set in Different

Cool/Heat Operation Mode

Check Sum Mis-matching

Fan Motor not Operating

Same as CH 04 (Float Switch

Open Circuit) or Unit under

Central Control

Not an Error, Press Timer & Min

Buttons Simultaneously for 3 seconds to Toggle On/Off

Not an Error, Press Jet Cool

Button to Toggle On/Off

Not an Error

Indoor

Status

Off

Off

Off

Off

Off

Macedo - November 2007

- 1 -


Outdoor Unit Faults can also be read from the outdoor unit PCB using the flashing LED’s as below:

Example: Error 21

Off

Off

Off

Off

Off

Off

Off

Off

Off

Error

code

Contents

21

IPM Fault (Compressor Over

Current)

22

CT 2 (Max. Current)

23

DC Link Low Volt.

24

25

Low / High Pressure

AC Low / AC High Volts.

26

DC Compressor Position

27

PSC Fault (Reactor)

28

DC Link High Volts

32

33

Discharge Pipe Temp. High (INV.

Compressor)

Discharge Pipe Temp. High

(Cons. Compressor)

40

CT Circuit

41

D-Pipe Sensor INV. Compressor

(Open/Short)

44

Air Sensor (Open/Short)

LED01G

(Red)

LED02G

(Green)

Case of Error

2 times 1 time

Compressor Malfunction, IPM

Fault

2 times 2 times Current is 14A ↑

2 times 3 times DC Link Voltage is 140V ↓

2 times

2 times

4 times

5 times

Low / High Press Switch OPEN

Circuit

Abnormal AC Input Voltage

(140V ↓ , 300V ↑)

2 times 6 times Position Detection Error

2 times 7 times Over Current at “IGBT”

2 times 8 times DC Link Voltage is 420V ↑

3 times

3 times

4 times

2 times

3 times

Discharge Sensor High Temp.

(105 o

C ↑)

Discharge Sensor High Temp.

(105 o

C ↑)

CT Circuit malfunction

4 times

4 times

1 time

4 times

Open / Short Circuit.

Open / Short circuit

45

Cond. Pipe Sensor (Open/Short) 4 times 5 times Open / Short circuit

46

47

Suction Pipe Sensor

(Open/Short)

D-Pipe Sensor Cons.

Compressor (Open/Short)

4 times

4 times

6 times

7 times



48 D-Pipe & Air Sensor (Open) 4 times 8 times Dual Sensor unplugged

51

Over Capacity

53

Communication Error (Indoor ↔

Outdoor)

60

EEPROM Check Sum

5 times 1 times Over Capacity Combination

5 times 3 times Poor/Loss of Communication

61

62

Cond. Pipe Sensor Temp. High

Heat Sink Sensor Temp. High

6 times

6 times 1 time

Check Sum Mis-Match

Cond. Temp. High (65 o

C ↑)

6 times 2 times Heat Sink Temp. High (85 o

C ↑)

65

Heat Sink Sensor (Open/Short) 6 times 5 times Open / Short circuit

The codes are explained in detail on the following pages.


- 2 -

Outdoor

Status

Off

Off

Off

Off

Off

Off

Off

Off

Off

Off

Off

Off

Off

Off


Fault Code 01

Is a fault with the Indoor unit return air Thermistor

Unplug the Thermistor from the PCB and Check its resistance check against this graph:

Resistance of Air thermistor

20

18

16

14

12

10

8

6

10 15 20 25 30 35 40

Temperature

Alternatively the sensor can be tested while still connected to the PCB measure the DC voltage across the thermistor and check it against the graph below.

Voltage across Air thermistor

3.5

3.0

2.5

2.0

1.5

10 15 20 25

Temperature

30 35 40


- 3 -


Fault code 02

Is a problem with the Indoor unit coil inlet Thermistor

Unplug the Thermistor from the indoor PCB and Check its resistance against this graph:

Coil thermistor resistance k Ohms

20

15

10

5

0

0 10 20 30 40 50 60 70

Temperature

Alternatively the sensor can be tested while still connected to the PCB measure the DC voltage across the resistor and check it against the graph below.

Voltage across coil thermistor

4.0

3.0

2.0

1.0

0.0

0 10 20 50 60 70 30

Temp

40


- 4 -


Fault Code 03

Indicates a wiring error between the remote controller and the fan coil, this is most common in group control applications where more than 1 fan coil is connected to a single remote controller.

Firstly check the wiring has been done correctly see below.

1 2 3

2 3

2 3

Next check the switch in the back of the remote controller, it has to be set to Group or GR1 for group control, the Factory setting is Single or SG, after setting the switch reset the power for 2 minutes. If the fault does not clear, check the Voltage of the remote controller cable.

The Red cable is 12 Vdc

The Brown (or Black) cable is Ground 0 Vdc

The Yellow is signal (Comms.)

Test

Voltage across the Red and Brown (or Black) cable this should be 12 Vdc.

Voltage from Yellow to Brown (or Black) should be fluctuating between 8 – 12 Vdc.


- 5 -


Fault Code 04

Fault code CH04 indicates that the float switch of the fan coil has risen.

On fan coils without a drain pump it indicates that the jumper (blue plug with 30mm of blue wire) in terminal

CN FLOAT is missing.

If the fan coil is running and the float rises it will take 3 ½ minutes for the fault to show on the controller, this is to give the unit time to pump excess water away. Once the float falls, (or the jumper is put back into the board) it will not be possible to clear the fault for 40 seconds. It is considered good practice to reset the power to clear this fault code.

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 system.

Testing

•

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 2MΩ).

•

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 18ºC; 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.


- 6 -


Fault code 06

Is a problem with the Indoor unit coil outlet Thermistor



20

15

10

5

0

0 10 20 30 40 50 60 70

Temperature



4.0

3.0

2.0

1.0

0.0

0 10 20 30

Temp

40 50 60 70


- 7 -


Fault Code 07

On Multi split systems, the first unit switched on is the cool heat master, the master tells the condensing unit what to do. If the condenser is in heating and any slave is set to cooling a CH07 fault code will appear.

Likewise if the condenser is in cooling and any slave is set to heating a CH07 fault code will appear. If the master is switched off the next longest running unit becomes the master.

To clear the fault turn off the unit at the remote controller, turn it back on again and change the

mode

Fault Code 09

Check the correct PCB assembly has been installed, check the EEPROM is securely pushed into its socket, check for dry joints, replace outdoor unit PCB if nothing is found.

Fault Code 10

This is a problem with the Indoor Fan Motor, where rotation is not detected, and could be result of either

Mechanical or Electrical failure.

•

Check that motor is free to rotate and not seized.

•

Check the motor is electrically sound, windings not Open or Short circuit.

•

Check power output from PCB to fan motor.

•

Check rotation feedback circuit.

More modern units use inverter fan motors, which are powered by a DC Voltage.

In reality these fan motors are AC fan motors with a small inverter-type circuit build inside. This inverter circuit is integrated with the fan motor and impossible to replace, you have to replace the entire fan motor.

Similar to inverter-controlled compressors, the speed of these fan motors can be changed to whatever is needed (within certain limits). In practice the change in fan speed is not ‘continuous’ but certain fixed speeds have been programmed inside the AC unit.

This type of fan control can be recognized by the 5 wires coming from the fan on a connector with 7 possible connections

These fan motors have 5 connections, power supply is 360VDC, and the speed is determined by a voltage ranging from 0 (0 rpm) to 5VDC (max speed) and a power supply for the internal electronics of 15VDC.

These motors are easy to identify from a wiring diagram, they always show them not connected to anything as the electronics are too difficult to draw on the diagram.

Detail of Hall Sensors

A Hall effect sensor works like a magnetic reed switch, one end is wired to a 15 Vdc supply and the other is the feed back to the PCB. As a magnet mounted on the rotor of the motor passes the hall sensor the reed switch closes momentarily and allows the DC signal to flow through it back to the PCB. The hall sensors have a resistance so the voltage fed back to the PCB will only be approximately 12V DC.

The pcb will know what speed the fan motor should be turning as it is also controlling the output of the inverter, if there is a discrepancy between the inverter output RPM and the feedback from the hall sensors a fault will occur. Usually the fan will rev very fast for a few seconds then stop this indicates hall sensor problems.

Replace either Fan Motor or Fan PCB as necessary.


- 8 -


Fault Code 21

This fault is caused by an over current in the inverters DC power circuit. If the DC part of the circuit exceeds

14 Amps fault code 21 will be displayed.

This is caused by either the inverter PCB being faulty or compressor being short circuit or down to earth.

Disconnect the electrical connections to the compressor and check the resistance of the compressor windings, measure from U to V, V to W and W to U the values should be between 0.25 and 5 Ohms each.

The next test is to measure the resistance of the compressor windings to earth.

Using a Megger (High Voltage Meter) measure the resistance from any of the 3 compressor terminals to an Earth point (pipe work).

The value should exceed 2 M Ohms.

If the compressors fail these tests it will need replacing.

If the compressor is OK you will need to check the inverter output voltages. Please see section on Inverter testing at end.

Fault Code 22

This fault is caused by a Compressor over-current see code 21

Please see section on Inverter testing at the end.

Fault Code 23

This fault indicates a fault in the DC part of the inverter circuit; it means that the DC Voltage to the inverter is below 140 V Dc, it should be 370 V for single phase machines and 600 V dc for three phase machines. The fault is usually caused by the inverter charging resistor being faulty; this component is mounted on the outdoor unit PCB and cannot be replaced.

Start the unit running and measure the DC Voltage supply to the inverter. This is easiest to measure at the inverter capacitors; it should be 370 V for single phase machines and 600 V dc for three phase machines

See section on Inverter testing at the end.


- 9 -


Fault Code 24

If the unit has a low or high pressure fault CH24 will display.

If the LP switch goes open circuit the compressor will be stopped, on inverter units this can take up to 30 seconds. The LP Switch goes open circuit when the suction pressure falls below 0.5 bar. The HP Switch opens at 41 bar.

The fault code will only occur if the pressure switch is tripped 5 times within 1 hour, this can only be reset by switching off the power to the condensing unit for 2 minutes.

If your unit does not have any pressure switches it may still have a plug on the outdoor unit PCB labelled CN

Press, it should have a link plugged in, if the link is missing it must be replaced. This link is not available as a

“Spares” part, please remember to transfer it across if you need to replace the PCB.

Fault Code 25

This fault indicates a problem with the incoming power supply to the system.

Measure the Voltage of the incoming supply, if it is less than 140V AC or greater than 300V AC this fault will occur.

If the Power supply is correct and the fault persists replace the outdoor unit PCB.

Fault Code 26

This fault indicates a problem with the positioning system of the inverter compressor, which indicates a seized compressor.

Firstly check the compressor is correctly connected. Next reset the power supply to the system ensuring the power is left off for 5 minutes. Start the unit up, after a couple of minutes the compressor will try and start, you can hear a high pitched whine when it does. If the compressor does not start turning within a couple of seconds the whining will stop. The compressor will try to start 3 times then the fault will recur.

Fault Code 27

This fault indicates a problem with the inverter module, see section on testing inverters. Also check reactor is connected to the PCB and check its resistance it should be well under 1 Ohm.

Fault Code 28

This fault indicates a problem in the DC part of the inverter circuit; it means that the DC Voltage to the inverter is too high.

Start the unit running and measure the DC Voltage supply to the inverter. This is easiest to measure at the inverter capacitors; it should be 370 V for single phase machines and 600 V dc for three phase machines. See section on Inverter testing at end.

Fault Code 32

Indicates that the Inverter compressor discharge temperature is high (above 105ºC) this usually indicates the system has either a shortage of refrigerant or a blockage in the system.

Reset the power to the unit for 2 minutes and restart it. If the compressor starts measure the compressor discharge temperature, typically it should not be more than 50ºC above the ambient temperature around the condensing unit. It may take quite a long period for the compressor to overheat so don’t just start the unit and run. Make sure you check the unit is operating correctly and providing adequate cooling.


- 10 -


Fault Code 33

Indicates that the fixed speed compressor discharge temperature is high (above 105ºC) this usually indicates the system has either a shortage of refrigerant or a blockage in the system.

Reset the power to the unit for 2 minutes and restart it, If the compressor starts measure the compressor discharge temperature, typically it should not be than 50ºC above the ambient temperature around the condensing unit. It may take quite a long period for the compressor to overheat so don’t just start the unit and run. Make sure you check the unit is operating correctly and providing adequate cooling.

Fault Code 40

This fault indicates a problem with the current drawn by the AC part of the inverter circuit.

Refer to the inverter testing procedure at the end.


- 11 -


Fault Code 41

This fault indicates an Inverter Compressor discharge Thermistor fault

Unplug the Thermistor and Check its resistance check against this graph:

Resistance of discharge pipe thermistor

250

200

150

100

50

0

20 30 40 50 60 70 80 90 100 110

temp


Voltage across discharge thermistor

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

20 30 40 50 80 90 60

Temp

70 100 110


- 12 -


Fault Code 44

Indicates a fault with the Outdoor unit air Thermistor


Resistance of Air thermistor

12

10

8

6

20

18

16

14

10 15 20 25 30 35 40

Temperature


Voltage across Air thermistor

3.5

3.0

2.5

2.0

1.5

10 15 20 25

Temperature

30 35 40


- 13 -


Fault Code 45

Indicates a problem with the condenser coil outlet Thermistor



20

15

10

5

0

0 10 20 30 40 50 60 70

Temperature



4.0

3.0

2.0

1.0

0.0

0 10 20 30

Temp

40 50 60 70


- 14 -


Fault Code 46

Indicates a problem with the compressor suction Thermistor



20

15

10

5

0

0 10 20 30 40 50 60 70

Temperature



4.0

3.0

2.0

1.0

0.0

0 10 20 30

Temp

40 50 60 70


- 15 -


Fault Code 47

Indicates an Inverter Compressor discharge Thermistor fault


Resistance of discharge pipe thermistor

250

200

150

100

50

0

20 30 40 50 60 70 80 90 100 110

temp


Voltage across discharge thermistor

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

20 30 40 50 80 90 60

Temp

70 100 110


- 16 -


Fault Code 51

This indicates that the capacity of the indoor unit / units is too great for the condensing unit. Make a note of the model number of the fan coil/coils and the condensing unit and check with the equipment supplier that the units you have installed can be connected together.

Fault Code 53, (see fault code 05)

Fault Code 54

This fault normally indicates a lost phase or the phases are reversed on the power supply to 3 phase units.

Check all 3 phases are available at the power terminals to the unit. You should have 415v AC across red to blue, blue to yellow and red to yellow,

If this is all ok turn off the power and swap the red and yellow cores of the power supply cable over, reset the power and the unit will operate.

Fault Code 60

Check the correct PCB assembly has been installed, check the EEPROM is securely pushed into its socket, check for dry joints, replace outdoor unit PCB if nothing is found.

Fault Code 61

Indicates the outdoor unit condenser coil temperature is high above 65ºC, this will usually be experienced in cooling mode and will indicate insufficient air being drawn over the coil.

Check there are no blockages to the coil (carrier bags dirt etc); check the air flow is not short circuiting from the front to the back of the unit and check for Nitrogen in the system.

Fault Code 62

Indicates the outdoor unit Inverter heat-sink thermistor has detected that the heat sink is overheating 85ºC.

This is usually caused by debris blocking the heat-sink fins or an error with the thermistor, see code 65.


- 17 -


Fault Code 65

Is a problem with the Inverter PCB heat sink thermistor for the heat sink on the outdoor unit PCB, unplug the

Thermistor from the PCB and Check its resistance against this graph:

resistance of Heat sink thermistor

20

18

16

14

12

10

8

6

10 15 20 25 30 35 40

Temperature


Voltage across Heat Sink thermistor

3.5

3.0

2.5

2.0

1.5

20 25 30

Temperature

35 40


- 18 -


Testing Inverters

It is best to test inverters with no compressors connected especially if you expect the compressor is at fault.

But if you remove the wires from the compressor and try to run the systems a fault will be displayed. The fault is caused by the inverter PCB being able to detect whether a compressor is connected or not. Most modern inverters are able to detect whether the compressor has been disconnected in only a few seconds making testing very difficult.

Testing can be done in two ways:

Firstly the hard way……

You will need a digital multi meter with a min max function,

Turn off the power

Disconnect the compressor either from the PCB or at the compressor terminals.

Connect your meter to two of the phases (Red to blue) set your meter to record max and min voltage

Power up and Start the unit

Let the inverter start and watch the Voltage rise

Record the maximum Voltage

The inverter will stop after a few seconds and the voltage will fall to 0

Swap the leads to measure the next two phases (Red to Yellow).

Measure as before

Repeat for the last two phases Blue to Yellow.

The readings of maximum voltage should be the same for all 3 measurements if not the inverter is faulty, the

PCB will need replacing.

If the readings are equal the Inverter is healthy and the compressor will need replacing.

And the easy way:

You will need an LG Inverter tester,

Turn off the power

Disconnect the compressor lead from the compressor terminals.

Connect your inverter tester to all 3 leads (polarity is not important)

Power up and Start the unit

Let the inverter start and watch the led’s

All 6 must light up and should be of equal brightness

The inverter will stop after a few seconds and the led’s will go out

If you miss the led’s (they will only light for a couple of seconds) the unit will try to start again 3 times with a 3 minute delay between each test

If all 6 led’s DON’T light up the inverter is faulty, the PCB will need replacing.

If the led’s all light up the Inverter is healthy and the compressor will need replacing.


- 19 -

Lg Multi Fault Codes

Resistance of Air thermistor

Voltage across Air thermistor

Coil thermistor resistance k Ohms

Voltage across coil thermistor

1 2 3

2 3

2 3

Coil thermistor resistance k Ohms

Voltage across coil thermistor

Resistance of Air thermistor

Voltage across Air thermistor

Coil thermistor resistance k Ohms

Voltage across coil thermistor

Coil thermistor resistance k Ohms

Voltage across coil thermistor

resistance of Heat sink thermistor

Voltage across Heat Sink thermistor

Testing Inverters

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