splits and multiSplit service information - Thermofrost...

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Split and Multi Split air conditioners

Service information

Programming LG wired controllers 2 New type 2

Old type 7

Fault codes 9

Wall units (single split) 9

Universal split and multi split 10

Detailed explanation of fault codes 12

Thermistor calibration figures 27

Testing the diodes in the inverter circuit 29

Last update: 14/1/2011

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Programming LG wired

controllers

1. New type PQRCUSA0 The new controller is model number PQRCUSA0.The same model is used for split and multi splits and for VRF. There is a built-in receiver which responds to an infra red controller when used in ducted units.

Updated 29/3/10

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User functions Setting the time

• Press the time button (13) for about 4 seconds until the display flashes

• Use the arrow keys to navigate around the sections and to set each item (hour, minutes, am/pm, day of week)

• Press OK/CLEAR (14) to confirm.

Child lock The Child Lock is used to prevent unauthorised changes to the controller settings. The controller does not respond to any button, until the lock is released

• Repeat pressing the FUNCTION SETTING button (7) until the child lock sign appears

• Press OK/CLEAR button (14) to confirm. CL will appear on the display

• Repeat the operation to release the child lock

Vane angle control • Repeat pressing the FUNCTION SETTING button (7) until the vane angle control sign

appears

• The display would show a pair of numbers, for example example The number to the left (2 in this example) is the vane number to be controlled. The number on the right (P1 in this example) is the vane angle.

• Use the keys to get the left number to flash.

• Use the up/down keys to select the vane number to be adjusted. The choice is 1,2,3,4 or All

• Use the left/right arrow keys to get the right hand number to flash. Then use

the up/down keys to select the required angle. P1 directs the air closest to the ceiling; P6 provides the steepest downwards flow.

• Press OK/CLEAR (14) to confirm

• Press ESC to leave the programming mode (the controller would automatically leave the programming mode if left for 25 seconds)

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Engineer functions The following functions can be programmed

No. Function Function Code

Value

1 Test run – 18 minutes, cooling, high fan speed,

01 01:Set

2 Address setting 02 00 to FF : Address 3 ESP value for ducted units 03 01:Very low

02:Low 03: Medium 04:High 05:Very high

4 Room temperature

thermistor 04 01:Remote controller sensor

02:Return air sensor 03:Both sensors

5 Ceiling height adjustment 05 01: Medium 02:Low 03:High 04:Very high

7 Two controllers on one indoor unit – one must be master, one slave

07 00:Slave 01:Master

9 Dry contact 09 00:Off 01:On

12 Centigrade to Fahrenheit 12 00:Centigrade 01: to Fahrenheit

Group control No programming required on controller. See Product Sheet 98 for dip switch settings on indoor unit PCB

The engineer functions are accessed by pressing the FUNCTION SETTING button for about 4 seconds, until the following appears on the display instead of the time-of-day:

Once you are in the programming mode, the function number advances each time you press the FUNCTION SETTING key. Repeat pressing this key until you reach the function code you need to set. When you have selected the function code, use the up/down arrow keys to obtain the required selection within that function code. Example: ceiling height adjustment (function 05) for medium ceiling height (selection 03) should display 05:03 Press the OK/CLEAR (14) to confirm the selection Then continue programming, or press the ESC button (8) to leave the programming mode (The programming mode exits automatically in any case after 25 seconds).

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7-Day Timer Setting (Technical sheet 107)

• Press the timer setting button (13) once, towards the bottom right side you’ll see flashing.

Repeat pressing (3 times) until is flashing.

• Scroll across to the required day that you wish to set using the (15). Press down (15). You can now see the number 1 flashing. Each controller can be set to operate up to two time run periods each day. ie, Number 1 09.00-12.00. Number 2 13.00-17.00.

1 signifies period one, 2 signifies period two. Press to scroll to between each period.

• To set the on/off time press once to select the hour on time and again to select the minute on time. The

up down buttons will adjust the time. Note that a hyphen appears on the right side of the 4 digit time.

• Now set the off time by pressing once. The hour time will now flash and the hyphen appears on the left

side of the 4 digit time to signify the off time. Adjust the hour and minute time accordingly using the buttons.

• Press once to return back to the time run period selection. Press to scroll to the next time run period

and press to exit back to the day selection and set the next day. To exit out completely press escape

(8). To save settings press ok/clear (14). Once fully out of the 7 day timer menu press escape once to show the current time on the display. A line will appear under any day that has a set run time.

• You can set a day not to run by using the ‘holiday’ feature. This is ideal for operation Monday to Friday only. To set a holiday escape completely out from the weekly reservation settings and press the timer setting

button once, towards the bottom right side you’ll see flashing. Repeat pressing button (4

times), you will now see flashing. Scroll across to the required day using the buttons, press

the button to select. A line replaces that specific day to signify holiday set. Press button again to unselect. Press escape to exit out.

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2. Older wired controller The wired remote controller has the following main functions:

Mode selection Mainly heating, cooling, and auto changeover at a specified temperature.

Temperature selection The display shows the set temperature. Pressing the button with the house symbol displays the actual room temperature. The display reverts back to room temperature after a few seconds.

Fan speed High, medium and low or automatic. On some model the fan speed may reduce when the set temperature is reached and the compressor is off. In the heating mode, the fan operates only when the indoor coil is warm.

Timer A seven day timer is built-in

Child lock This is used to lock the controller at a set position to prevent unauthorised tampering. To lock, press Timer and Min buttons together for about 3 sec till CL shows To unlock, press Timer and Min together for about 3 sec till CL disappears When locked, CL appears for a few seconds each time any button is pressed, but the controller does not respond.

Swing The louvers may me set to either stay in one position, or swing

Vane angle control (cassettes) This permanently sets the angle of the vanes when the swing function is not in use. Each pair of vanes is adjusted separately. Press right arrow + Swing for 3 sec till PO is displayed (the default position) Keep pressing the swing button to change the angle between P0 and P5. Press Right arrow + swing to complete and set. This sets the angle on one pair of louvers. For the other pair, repeat the above using the left arrow key instead of the right arrow.

Test mode In this mode the unit operates continuously for 18 minutes, ignoring the room thermostat. Press house button + hour button for 3 second, till display shows LO. The test may be stopped early using the on/off button.

Alternative room thermostats There are two alternative room thermostats. The installer can select the return air thermostat, the controller thermostat, or a combination of both. A switch is provided at the back of the controller for this purpose. Top position – remote controller Mid position – indoor unit Lower position – both

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Fault codes

Wall units (single split) A summary of the fault codes is given in the table below, but they are described in greater detail in the pages that follow.

Display Error Code

Flashing Lights

Fault Indoor Outdoor

Indoor operation

C1 or CH1

1 Indoor temperature sensor open or closed circuit

O ON

C2 or CH2

2 Indoor temperature sensor open or closed circuit

O O ON

C4 0r CH4

4 Heat sink temperature sensor open or closed circuit

O O ON

C5 or CH5

5 Communication between indoor and outdoor units

O O OFF

C6 or CH6

6 Excessive current at inverter DC power circuit (can be indoor pipe outlet sensor, or outdoor condenser sensor on some models)

O O SHUT DOWN

C7 or CH7

7 Excessive compressor current O O SHUT DOWN

C8 or CH8

8 Indoor fan not rotating O OFF

C9 or CH9

9 Outdoor fan not rotating O O OFF

CA 10 1. Discharge temp more than 130 0C 2. Faulty discharge thermistor

O O ON

CC 2 + 1 EEPROM error O ON

CD 3 + 1 Inverter module error O ON

CE 4 + 1 O ON

Po System in Power Mode – not a fault

O

Lo System in test mode – not a fault

O

Notes: On models with an alpha-numeric display the error codes are as per the left hand column above. On other models the fault is determined by counting the number of flashes on one or two led’s. There is an interval of three seconds between repeats of the flashing sequence.

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Universal units including multi-split If there is a fault on any LG Universal unit, a two digit number will appear on the remote controllers led display. If the unit does not have a remote controller the fault will be displayed using the LED's on the front of the indoor unit.

The “Units” digit of the fault code is shown by the power led which has the following symbol by it. This is usually Red, but on a few models it is Green.

The “Tens” digit will be displayed by one other led, usually the “Sleep” or “Filter” lamp. Error

Indicator:

• The function provides self-diagnosis and displays an error code if there is any trouble.

• Error codes are displayed on the Indoor unit’s Wired Remote as CH**, and/or Fascia Display. In addition, the code is indicated via LED’s on the outdoor unit control board.

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

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

Indoor Unit Faults:

Error code

Contents Case of error Indoor Status

01 Air sensor (open/short) Open / Short circuit Off

02 Inlet pipe sensor Open / Short circuit Off

03 Communication(Indoor ↔ Wired R/Control)

Communication Poorly Off

04 Drain pump / Float switch Float switch Open circuit (High level water alarm)

Off

05 Communication(Indoor ↔ Outdoor) Communication Poorly Off

06 Outlet pipe sensor Open / Short circuit Off

07 Different operation mode Indoor units set in different operation modes Off

09 Checksum Error Defective PCB or EEPROM Connections Off

10 BLDC Motor Fan Lock (Indoor) Fan Motor or PCB Defective Off

HL Hard Lock (Controlled by External Source) Controlled by Dry Contact or Central Controller Off

CL Child Lock Function selected Not an error, press Timer & Min buttons simultaneously for 3 seconds to toggle On/Off

On

Po Jet Cool Mode selected Not an error, press Jet Cool button to toggle On/Off

On

Tens Units

Units Digit (Red) Tens Digit (Green)

Macedo - Oct 2010 - 9 -

LG Air Conditioning - Universal Split Fault Codes Sheet

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

Error code

Contents LED01G

(Red) LED02G (Green)

Case of Error Outdoor Status

21 IPM Fault (Compressor Over current) 2 times 1 time Compressor malfunction, IPM Fault

Off

22 CT 2 (Max. Current) 2 times 2 times Current is 14A ↑ Off

23 DC Link Low Volt. 2 times 3 times DC Link volt. Is 140V ↓ Off

24 Low / High Pressure 2 times 4 times Low / High press switch OPEN Off

25 AC Low / AC High Volts. 2 times 5 times Abnormal AC volt. Input. Off

26 DC Compressor Position 2 times 6 times Off

27 PSC Fault (Reactor) 2 times 7 times Off

28 DC Link High Volts 2 times 8 times Off Off

29 COMP Over Current 2 times 9 times Inverter Compressor input current is over 30A

Off

32 Discharge Pipe Temp. High (INV) 3 times 2 times D-Pipe Temp (Inv.) >105°C Off

33 Discharge Pipe Temp. High (Cons.) 3 times 3 times D-Pipe Temp (Const) >105°C Off

39 Communication Error 3 times 9 times Communication Error Between PFC and INV PCB’s

Off

40 CT Circuit 4 times CT Circuit malfunction Off

41 D-Pipe sensor INV. (Open/Short) 4 times 1 time Open / Short circuit. Off

44 Air sensor (Open/Short) 4 times 4 times Open / Short circuit Off

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

46 Suction Pipe Sensor (Open/Short) 4 times 6 times Open / Short circuit Off

47 D-pipe Sensor Cons. (Open/Short) 4 times 7 times Open / Short circuit Off

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

51 Over Capacity 5 times 1 times Over Load Combination Off

52 Communication Error (Main micom ↔ Sub micom)

5 times 2 times Poor/Loss of Communication Off

53 Communication Error (Indoor ↔ Outdoor)


54 Outdoor 3-Phase Power Supply Reverse Phase / Missing Phase

5 times 4 times Incorrect Wiring Off

60 EEPROM Check Sum 6 times Check Sum Mis-Match Off

61 Cond. Pipe Sensor Temp. High 6 times 1 time Cond. Temp. High Off

62 Heat Sink Sensor Temp. High 6 times 2 times Heat Sink Temp. High Off

63 Cond. Pipe Sensor Temp. Low 6 times 3 times Cond. Temp. Low Off

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

67 Outdoor BLDC Fan Lock 6 times 7 times Fan Motor/Circuit Problem Off

73 PFC Fault Error (S/W) 7 times 3 times Inverter PCB input current is over 48A (Peak) for 2ms

Off

105 Comms. Error (Main board ↔Fan board)


[The codes are explained in detail on the following pages]

Macedo - Oct 2010 - 10 -


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:

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.

Volts DC

3.5

3.0

2.5

2.0

1.5

10 15 20 25 30 35 40

Voltage across Air thermistor

Temperature

Resistance k Ohms 20

18

16

14

12

10

8

6

10 15 20 25 30 35 40

Resistance of Air thermistor

Temperature

Macedo - Oct 2010 - 11 -


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:


Vo

lts D

C

4.0

3.0

2.0

0.0

1.0

0 10 20 30 40 50 60 70

Voltage across coil thermistor

Temp

Resis

tance k

Ohm

s20

15

10

5

0

0 10 20 30 40 50 60 70

Coil thermistor resistance k Ohms

Temperature

Macedo - Oct 2010 - 12 -


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.

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 or 0 Vdc The Yellow is signal (Comms.)

Test Voltage across the Brown/ Black cable and the Red, this should be 12 Vdc Voltage from Yellow to Brown/Black this should be fluctuating between 8 – 12 Vdc.

2 3

1 2 3 2 3

Macedo - Oct 2010 - 13 -


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 1/2 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

These error codes indicate a communication fault between the indoor and outdoor units; it appears approximately 5 minutes after powering up the system.

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 on the Wired Remote within 5 mins. of powering up the system.

Testing First check for any isolator or switches on the interconnecting cable and ensure both the Comms and Neutral are un-switched. Then confirm connections are correct and secure at both the Indoor and Outdoor units. Check if any other devices are connected on the interconnecting cable, remove such equipment, and connect them elsewhere.

Open the outdoor unit to reveal the Main PCB and identify the Green and Red LED’s on that board. The Green LED should be lit steadily if power is present, the Red LED should be doing one of the following:-

1. If the outdoor unit receives communications from the indoor unit, the Red LED should be flickering. 2. If the Red LED glows steadily without flickering, then no communication is being received from the

indoor unit. Check the interconnecting cables for any short or open circuits, not forgetting the connecting cables between the terminal rail and PCB on both Indoor & Outdoor units. Repair wiring, or replace the Indoor PCB as necessary.

3. If the Red LED does not light at all, then the fault is with the outdoor PCB, or connections to it. Confirm that the Outdoor PCB is receiving power (Green LED lit). Repair wiring, or replace the Outdoor PCB as necessary.

4. If Condition 3 above applies please check the following and repair/replace as required. Failure to do so may result in the new PCB becoming damaged.

a. Check PCB Control Fuse, if blown, identify cause and rectify. b. Check Fan Motor(s).

i. AC Motors for Short Circuits or Down to Earth. ii. BLDC Motors (See Product Technical Update - Sheet 83).

c. Reversing Valve Coil, for Short Circuit or Down to Earth. d. Reactor, for Open Circuit. e. Electronic Expansion Valve Down to Earth (See Product Technical Update - Sheet 96). f. Compressor, for Short Circuit or Down to Earth.

Additional Tests: Set your meter to DC Volts, Test between terminals 2 and 3 of the outdoor unit and wiring terminals, you should see 0-75 Vdc, it will be fluctuating rapidly.

If this signal voltage is not present disconnect the wire from terminal 3 of the inter unit cabling, and test terminal 3 Voltage again. If Voltage is still not present, the outdoor PCB must be faulty.

If this signal voltage is detected leaving the outdoor unit, reconnect wire 3 and check what is being received at the indoor unit. Disconnect wire 3 from the indoor terminal block and check the DC Voltage between this wire and terminal 2. It should be the same as what you saw at the outdoor unit, if not your wiring is at fault.

With the wire still disconnected, check between terminals 2 & 3. You should see a relatively steady voltage in the range of 0.5 – 15Vdc (Negative). Any significant difference would indicate a faulty Indoor PCB.

Important: Comms Errors are also created on Universal “Synchro Systems” when they are not configured/commissioned correctly. Please follow the correct Synchro Commissioning Procedures.

Macedo - Oct 2010 - 14 -


Fault Code 06

Is a problem with the Indoor unit coil outlet Thermistor



Vo

lts D

C

4.0

3.0

2.0

0.0

1.0

0 10 20 30 40 50 60 70


Temp

Resis

tance k

Ohm

s

20

15

10

5

0

0 10 20 30 40 50 60 70


Temperature

Macedo - Oct 2010 - 15 -


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 for loose connections or dry joints where EEPROM connects on Main PCB, repair if possible, if not replace PCB.

Fault Code 10

Indoor Fan Motor problem, See Fault Code 67 for Troubleshooting help.

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

Macedo - Oct 2010 - 16 -


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.

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, and if the link is missing it must be replaced.

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 29

Check and correct for any: 1. Overload operation (Pipe restrictions / Restricted Airflow / EEV defect / Refrig. Overcharged) 2. Compressor damage (Insulation damage / Motor damage) 3. Input Voltage Low 4. ODU Inverter PCB assembly damage

Macedo - Oct 2010 - 17 -


Fault Code 32

Indicates that the Inverter compressor discharge temperature is high (above 105°C) 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 50°C 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 33

Indicates that the fixed speed compressor discharge temperature is high (above 105°C) 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 50°C 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 39

Check and repair or replace as necessary: 1. PCB defect / Wiring defect

2. Different Micom Software Version 3. ODU Inverter PCB assembly damage

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.

Macedo - Oct 2010 - 18 -


Fault Code 41

This fault indicates an Inverter Compressor discharge Thermistor fault Unplug the Thermistor and Check its resistance check against this graph:


Voltage DC

4.5

4.0

5.0

3.5

3.0

2.5

2.0

1.5

1.0

20 30 40 50 60 70 80 90 100 110

Voltage across discharge thermistor

Temp

resistance kOhms

250

200

150

100

50

0

20 30 40 50 60 70 80 90 100 110

Resistance of discharge pipe thermistor

temp

Macedo - Oct 2010 - 19 -


Fault Code 44

Indicates a fault with the Outdoor unit air Thermistor

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


Volts DC

3.5

3.0

2.5

2.0

1.5

10 15 20 25 30 35 40

Voltage across Air thermistor

Temperature

Resistance k Ohms 20

18

16

14

12

10

8

6

10 15 20 25 30 35 40

Resistance of Air thermistor

Temperature

Macedo - Oct 2010 - 20 -


Fault Code 45

Indicates a problem with the condenser coil outlet Thermistor



Vo

lts D

C

4.0

3.0

2.0

0.0

1.0

0 10 20 30 40 50 60 70


Temp

Resis

tance k

Ohm

s

20

15

10

5

0

0 10 20 30 40 50 60 70


Temperature

Macedo - Oct 2010 - 21 -


Fault Code 46

Indicates a problem with the compressor suction Thermistor



Vo

lts D

C

4.0

3.0

2.0

0.0

1.0

0 10 20 30 40 50 60 70


Temp

Resis

tance k

Ohm

s

20

15

10

5

0

0 10 20 30 40 50 60 70


Temperature

Macedo - Oct 2010 - 22 -


Fault Code 47

Indicates an Inverter Compressor discharge Thermistor fault Unplug the Thermistor from the PCB and Check its resistance check against this graph:


Voltage DC

4.5

4.0

5.0

3.5

3.0

2.5

2.0

1.5

1.0

20 30 40 50 60 70 80 90 100 110

Voltage across discharge thermistor

Temp

resistance kOhms

250

200

150

100

50

0

20 30 40 50 60 70 80 90 100 110

Resistance of discharge pipe thermistor

temp

Macedo - Oct 2010 - 23 -


Fault Code 48 This fault indicates that the compressor discharge sensor and the condenser air temperature sensors are both unplugged. Both these sensors are connected to a single connector on the outdoor unit PCB, plug it in and the fault will go away.

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 52

This fault code indicates a communication error between the Main and Sub micom (CPU’s) on the outdoor unit main PCB. Check for evidence of damage, if none found reset power, if fault reappears replace pcb.

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 for dry joints, replace outdoor unit PCB if nothing is found.

Fault Code 61

Indicates the outdoor unit condenser coil temperature is high above 65°C, 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 85°C. This is usually caused by debris blocking the heat-sink fins or an error with the thermistor, see code 65.

Macedo - Oct 2010 - 24 -


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:


Volts DC

3.5

3.0

2.5

2.0

1.5

20 25 30 35 40

Voltage across Heat Sink thermistor

Temperature

Resistance k Ohms

20

18

16

14

12

10

8

6

10 15 20 25 30 35 40

resistance of Heat sink thermistor

Temperature

Macedo - Oct 2010 - 25 -


Fault Code 67

This is a problem with the Outdoor 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 Motor or Fan PCB as necessary.

Fault Code 73

Check and repair or replace as necessary:

1. Overload operation (Pipe restrictions / Restricted Airflow / EEV defect / Refrig. Overcharged) 2. Compressor damage (Insulation damage / Motor damage) 3. Input Voltage abnormal 4. Power supply wiring abnormal 5. Inverter PCB assembly damage

Fault Code 105

This is due to a Communication error between the Main outdoor PCB and Fan PCB.

• Check for Open/Short of communication line between the Main and Fan PCB’s.

• Check communication cable plug connections. • Is the communication LED on?

26


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.

29

Testing the inverter circuit diodes using a diode tester Many multi-meters have a diode test facility, which can be used as shown below. This tests the diodes but does not dhow whether they are powered-up. An inverter tester does indicate that the diodes are powered.

Copyright 2010@LG Electronics / AC Company All Rights ReservedService Engineering Inverter Guide 25252525

1.3 Measures for Main Error Codes CH21 (Comp IPM Fault)

3.3.1.4 IPM Check

PurposeJudgment of the IPM part fault of PCB assembly.

Items for checking

1. Judgment of damage of IGBT

2. Checking the soldering state

� How to check IPM IGBT (Diode Mode)

1. Remove the connector from PCB.2. Set the Multi-Tester as Diode Voltage Measurement Mode. ( )

3. Measure the voltages of P~U / P~V / P~W as shown in Fig. 1.4. Measure the voltages of U~Nu / V~Nu / W~Nu as shown in Fig. 2. 5. If the measurements are significantly different from the levels shown in the figures, the IPM is deemed to be damaged.

[Fig. 1]

27 26 25 24 23 22 21

P W V U Nu Nv Nw

0.4 ~ 0.6 V

27 26 25 24 23 22 21

P W V U Nw Nv Nu

0.4 ~ 0.6 V

Black Red Black Red

①①①① ②②②② ③③③③ ①①①① ②②②② ③③③③Sequence of Measurement

Measurement

Normal Standards

1 P-U 0.4V~0.6V

2 P-V 0.4V~0.6V

3 P-W 0.4V~0.6V

[Fig. 2]

Sequence of Measurement

Measurement

Normal Standards

1 U-Nu 0.4V~0.6V

2 V-Nv 0.4V~0.6V

3 W-Nw 0.4V~0.6V

②②②② ③③③③①①①①

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