What does LG Mini Split Ice on Coils - Causes & Fix mean?

Ice on coils is usually a dirty filter blocking airflow. Clean or replace the indoor filter, then power off for 2 hours to defrost fully.

How do I fix LG Mini Split Ice on Coils - Causes & Fix?

Follow the step-by-step diagnosis below. The most likely fix is identified by checking power, sensor resistance, and control-board signals in order — using a multimeter and the part numbers documented in the parts reference table.

Can I keep running the equipment with this fault active?

Generally no. Faults on Hvac units are emitted when a sensor, safety, or control circuit is outside its operating envelope. Running through an active fault risks compressor, heater, or control-board damage. Diagnose and clear the fault first.

What part is most commonly replaced for LG Mini Split Ice on Coils - Causes & Fix?

The most frequently replaced parts for LG Mini Split Ice on Coils - Causes & Fix are listed in the Parts Reference section of this guide with OEM part numbers and typical price ranges. Check the table for direct replacements.

Is LG Mini Split Ice on Coils - Causes & Fix a DIY repair or do I need a technician?

Sensor swaps, fan motor replacements, and condenser cleaning are typical DIY-level repairs. Anything involving refrigerant, gas, or high-voltage (>240V) work requires a licensed technician for both safety and code-compliance reasons.

LG Mini Split Ice on Coils - Causes & Fix

LG Mini Split Ice on Coils — What’s Happening

Ice forming on the indoor coil of your LG mini split is a symptom, not a fault code itself. It means the evaporator coil temperature has dropped below freezing because of restricted airflow, low refrigerant charge, or a faulty temperature sensor. When airflow across the coil is blocked by a dirty filter, clogged blower wheel, or dirty coil, the refrigerant cannot pick up enough heat and the coil surface freezes. Low refrigerant from a leak also causes coil temperatures to fall too low.

On some LG models you may also see error code CH12, which indicates an indoor middle pipe sensor or coil thermistor circuit problem. This sensor tells the control board the coil temperature. If it reads incorrectly or has a loose connection, the unit cannot regulate coil temperature properly and ice can form. Always confirm the exact meaning of any code using your model’s service documentation, because LG codes vary by series.

Jump to Fix

Most Likely Causes

Dirty or clogged indoor air filter A blocked filter is the most common cause, reducing airflow across the evaporator coil and allowing ice to form.
Dirty blower wheel or weak indoor fan motor Dust buildup on the blower wheel or a failing fan motor cuts airflow, causing coil temperatures to drop below freezing.
Dirty evaporator coil Matted dust or debris on the coil fins restricts heat exchange and allows ice to accumulate.
Low refrigerant charge or leak Undercharged refrigerant lowers evaporator pressure and temperature, freezing moisture on the coil surface.
Faulty middle pipe sensor or thermistor (CH12 code) An open, shorted, or damaged coil temperature sensor prevents accurate temperature control and can trigger icing.
Loose or corroded sensor wiring or connector A poor connection at the indoor board or sensor plug causes intermittent or incorrect temperature readings.
Indoor control board issue A failed control board input circuit is less common but can prevent proper coil temperature regulation even when the sensor is good.

How to Diagnose and Fix

Turn off the system and let the coil fully defrost for at least two hours before attempting any diagnostics or performance tests.
Remove and inspect the indoor air filter for dirt or blockage, then clean or replace it if clogged.
Check the indoor blower wheel for dust or matting and clean it carefully, then verify the fan motor spins freely and runs at normal speed.
Inspect the indoor evaporator coil for dirt, debris, or matted fins and clean the coil with approved coil cleaner if contaminated.
If your unit shows CH12 or similar pipe sensor codes, test the middle pipe thermistor and its harness for opens, shorts, or loose connectors at the indoor board.
Check refrigerant pressures, superheat, and subcooling using gauges and the model’s service manual targets to identify undercharge or leaks.
If airflow and sensor checks pass, inspect the indoor control board for damage, corrosion, or poor solder joints on the sensor input circuit.
After repairs, run the unit in cooling mode for at least 30 minutes and verify stable operation with no ice formation or recurring codes.

Parts You Might Need

Part	Notes
Indoor air filter (washable or replaceable)	Amazon \| Model-specific; check your unit’s documentation for the correct filter type and size.
Indoor coil pipe thermistor / middle pipe sensor	Amazon \| Identified by CH12 code; verify part number from your exact LG model service manual.
Indoor fan motor	Amazon \| Required if airflow remains low after cleaning the blower wheel and coil; match motor voltage and RPM to your chassis.
Indoor control PCB	Amazon \| Only if sensor circuit tests good but fault persists; confirm board part number for your model and revision.

If your appliance also shows a code on the display, these match this problem:

When to Call a Pro

Call a qualified HVAC technician if ice returns after cleaning the filter and defrosting the coil, if you see a CH12 or other sensor code and are not comfortable testing thermistors and wiring, or if you suspect low refrigerant. Refrigerant work requires EPA certification, proper gauges, and recovery equipment. A pro will also have access to the exact service manual for your LG model, including resistance tables, pressure specs, and board-level diagnostics that are not published in generic support articles.