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Error code reference

LG Hvac Error Code 6

LA09xHV/LA12xHV/LS902HPV/LS122HPV

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LA09xHV/LA12xHV/LS902HPV/LS122HPV: DC Peak Error or condenser coil over 149°F. All other Inverters: PCB sees IDU outlet pipe thermistor as open or shorted. PTAC: DIP switches 3,4,5 for temperature limiting not set properly.

First step from the service manual

For DC peak error: verify proper 208/240V AC, verify 3 compressor wires not switched, verify compressor not seized, verify 1-4Ω between compressor terminals. For condenser over-temp: verify thermistor accuracy. For other inverters: 2,800Ω at 38°C/100°F & 10,000Ω at 10°C/50°F.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 6 means on a LG hvac

Error code 6 on LG HVAC systems carries different meanings depending on the specific model. On LA09xHV, LA12xHV, LS902HPV, and LS122HPV units, this code indicates either a DC peak error in the inverter compressor circuit or an overtemperature condition at the condenser coil exceeding 149 degrees Fahrenheit. On all other LG inverter models, the indoor unit PCB has detected that the IDU outlet pipe thermistor is either open or shorted. On PTAC models, the code points to incorrect DIP switch configuration, specifically switches 3, 4, and 5 used for temperature limiting.

For the DC peak error on the designated inverter models, the fault occurs when the inverter board detects an abnormal current spike in the compressor drive circuit. This can stem from incorrect supply voltage, miswired compressor terminals, a seized compressor, or compressor winding resistance outside the acceptable range of 1 to 4 ohms between terminals. The condenser over-temp condition on those same models means the system is operating beyond safe thermal limits, often due to restricted airflow or a failed condenser fan.

On other inverter models, the outlet pipe thermistor is a negative temperature coefficient sensor. A healthy thermistor reads approximately 10,000 ohms at 10 degrees Celsius (50 degrees Fahrenheit) and approximately 2,800 ohms at 38 degrees Celsius (100 degrees Fahrenheit). Readings outside these values indicate a failed sensor or a wiring fault. On PTAC units, no electrical component has failed. Instead, DIP switches 3, 4, and 5 must be reconfigured correctly to clear the fault.

Source: manufacturer service documentation.

Common causes of 6

  1. 01

    Faulty or out-of-range IDU outlet pipe thermistor

    Part replacement

    On most LG inverter models, the most common trigger is a failed indoor outlet pipe thermistor. Check resistance: the sensor should read approximately 10,000 ohms at 10 degrees Celsius and 2,800 ohms at 38 degrees Celsius. Values outside this range confirm a failed sensor.

  2. 02

    DC peak error from incorrect supply voltage

    Wiring / connection

    On LA09xHV, LA12xHV, LS902HPV, and LS122HPV units, the inverter board may trigger a DC peak fault if the supply voltage is not within the proper 208/240V AC range. Verify incoming voltage at the unit before suspecting compressor or board faults.

  3. 03

    Miswired or seized compressor

    Part replacement

    Switched compressor wiring or a seized compressor can both cause a DC peak fault on compatible inverter models. Verify the three compressor wires are connected in the correct order and confirm winding resistance measures 1 to 4 ohms between terminals.

  4. 04

    Condenser coil overtemperature above 149 degrees Fahrenheit

    Wiring / connection

    On the designated inverter models, restricted airflow through the condenser or a failed condenser fan can push coil temperatures above the 149 degree Fahrenheit threshold. Inspect the condenser section for blockages and verify fan motor operation.

  5. 05

    Incorrect PTAC DIP switch settings

    Wiring / connection

    On PTAC units, error code 6 appears when DIP switches 3, 4, and 5 are not configured correctly for temperature limiting. No component has failed in this case. Locate the DIP switch block and adjust switches 3, 4, and 5 per the correct configuration for your installation.

See the test procedure for each cause

Frequently asked questions about 6

What does 6 mean on a LG hvac?
Error code 6 on an LG HVAC system has three possible meanings depending on the model. On LA09xHV, LA12xHV, LS902HPV, and LS122HPV units, it signals either a DC peak fault in the compressor inverter circuit or a condenser coil temperature exceeding 149 degrees Fahrenheit. On all other LG inverter models, the indoor unit PCB has detected that the outlet pipe thermistor is open or shorted. On PTAC models, DIP switches 3, 4, and 5 are not configured correctly for temperature limiting.
Can I fix error code 6 on my LG HVAC myself?
PTAC users can resolve the error themselves by reconfiguring DIP switches 3, 4, and 5 without any tools or parts. For inverter models, checking condenser airflow and inspecting for obvious wiring issues is within reach for a knowledgeable DIYer. However, testing compressor winding resistance, measuring supply voltage, and replacing thermistors or inverter boards requires proper tools and electrical knowledge, so most repairs should be handled by a qualified technician.
Is error code 6 on an LG HVAC dangerous?
The error itself is a protective fault, meaning the system has shut down to prevent damage rather than continuing to operate unsafely. A seized compressor or severely overheating condenser coil should not be ignored, as continued attempts to run the system could cause further electrical or mechanical damage. Address the root cause promptly rather than repeatedly resetting the unit.
How much does it cost to repair error code 6 on an LG HVAC?
Repair costs vary widely depending on the root cause. Replacing an IDU outlet pipe thermistor is a relatively inexpensive repair, typically ranging from around 50 to 150 dollars in parts plus labor. A failed compressor is the most expensive scenario, with replacement costs potentially ranging from several hundred to over a thousand dollars depending on the unit size. Reconfiguring PTAC DIP switches costs nothing if done without a service call.
Will resetting my LG HVAC clear error code 6?
A power reset may temporarily clear error code 6, but the fault will return if the underlying cause has not been resolved. On PTAC units, the error will persist until DIP switches 3, 4, and 5 are set correctly. On inverter models, the board will continue to detect the thermistor fault or compressor issue on the next operating cycle, so the error will reappear. Resetting without diagnosing the cause is not a solution.

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