Samsung Mini Split Ice on Coils - Causes & Fix

Samsung Mini Split Ice on Coils — What’s Happening

Ice forming on the indoor evaporator coil means the coil is running below 32°F for an extended period, which prevents the system from absorbing heat from your room air. This is a symptom, not a specific Samsung error code, though it can sometimes trigger sensor fault codes like E123 (indoor heat exchanger temperature sensor error) if the coil sensor fails or reads incorrectly.

The ice buildup usually points to an airflow restriction, a refrigerant charge problem, or a failed temperature sensor. Samsung’s service guidance highlights that defective room temperature sensors or heat exchanger temperature sensors can cause icing complaints when the control board cannot accurately monitor coil temperature.

Jump to Fix

Most Likely Causes

• Dirty air filter or blocked evaporator coil Restricted airflow is the most common cause because the coil cannot absorb enough heat and its temperature drops below freezing.
• Dirty or clogged blower wheel Dust buildup on the blower wheel reduces indoor fan performance and starves the evaporator of airflow, leading to icing.
• Blocked return or supply air path Furniture, curtains, or closed vents can choke off airflow to the indoor unit and cause the coil to freeze.
• Low refrigerant charge or refrigerant leak Low suction pressure from a leak drops the evaporator saturation temperature below freezing and causes ice to form on the coil.
• Faulty indoor coil temperature sensor (thermistor) An open, shorted, or out-of-calibration heat exchanger sensor can misreport coil temperature and allow icing or trigger error code E123.
• Damaged sensor wiring or loose connector Broken, corroded, or loose wiring between the sensor and the indoor PCB can mimic a bad sensor and cause intermittent icing or fault codes.
• Indoor control board (PCB) failure If the board cannot read the sensor correctly or has failed control logic, it may mismanage cooling cycles and allow coil icing.

How to Diagnose and Fix

1. Power off the unit and let the indoor coil defrost completely before testing to avoid false readings and water damage.
2. Remove and inspect the indoor air filter, clean or replace it if dirty, and confirm the filter slot is not blocked.
3. Check the indoor evaporator coil and blower wheel for dust or debris buildup and clean both if necessary.
4. Verify strong airflow by running the unit in cool mode with the fan on high and checking that return and supply air paths are unobstructed.
5. Inspect the indoor coil thermistor and room temperature sensor wiring for loose connectors, visible damage, or corrosion.
6. Measure the resistance of the heat exchanger temperature sensor with a multimeter and compare to the manufacturer’s chart if available (open reading indicates failure).
7. If airflow and sensors test good, check for signs of refrigerant leak (oil residue, frost on line set) and measure suction pressure if equipped.
8. If a leak or low charge is confirmed, recover the refrigerant, repair the leak, evacuate the system, and recharge to the nameplate weight specification.

Parts You Might Need

Related Error Codes

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

• Samsung Mini Split E1 01 error code
• Samsung Mini Split E3 01 error code
• Samsung Mini Split E4 01 error code
• Samsung Mini Split E5 01 error code

When to Call a Pro

Call a qualified HVAC technician if airflow cleaning does not resolve the icing, if you see refrigerant leak signs (oil or frost on piping), if error code E123 or another sensor fault appears, or if you need to test sensor resistance, check refrigerant pressures, or replace the indoor PCB. Refrigerant work requires EPA-certified recovery, evacuation, and recharge equipment and is not a DIY repair.