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Error code reference

Samsung Air Conditioner Error Code sx

Simultaneous breakaway of indoor unit EVAP IN and EVAP OUT sensors on xth indoor unit.

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Simultaneous breakaway of indoor unit EVAP IN and EVAP OUT sensors on xth indoor unit.

First step from the service manual

Check breakaway of each sensor; reassemble to correct.

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

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What sx means on a Samsung air conditioner

The Samsung air conditioner error code "sx" indicates the simultaneous disconnection or breakaway of both the EVAP IN (evaporator inlet) and EVAP OUT (evaporator outlet) temperature sensors on the xth indoor unit in a multi-unit system. The "x" in the code is a variable that identifies the specific indoor unit number experiencing the fault. These two sensors are thermistors mounted at the inlet and outlet of the evaporator coil, and they work together to allow the system's control board to monitor refrigerant temperatures, calculate superheat, and regulate compressor and expansion valve operation.

When both sensors detach or lose contact simultaneously, the system loses its ability to monitor evaporator coil temperature at either end. This is distinct from a sensor failure caused by electrical resistance drift or wiring faults. A simultaneous breakaway of both sensors points strongly toward a physical mounting issue rather than an electrical failure, since it is statistically unlikely for both thermistors to fail electronically at the same time. The sensors are typically clipped or strapped to refrigerant lines, and vibration, improper installation, or mechanical disturbance during maintenance can cause both to detach.

Diagnosing this fault requires a physical inspection of the evaporator coil area inside the affected indoor unit. Each sensor should be located, inspected for secure mounting contact with the refrigerant tubing, and reattached correctly if found loose or detached. After reassembly, clearing the fault and confirming that the control board receives valid temperature readings from both sensors is necessary before returning the unit to service.

Source: manufacturer service documentation.

Common causes of sx

  1. 01

    Physical sensor clip or strap failure

    Wiring / connection

    The thermistors are held against the evaporator tubing by plastic clips or wire straps that can loosen over time due to vibration or age. Inspect the mounting hardware and replace or reattach as needed.

  2. 02

    Displacement during maintenance or service

    Wiring / connection

    If the indoor unit was recently cleaned, serviced, or had its evaporator coil accessed, the sensors may have been knocked loose during that process. Check both sensor positions immediately after any recent service work.

  3. 03

    Excessive vibration from the unit

    Wiring / connection

    Prolonged mechanical vibration from the indoor unit blower assembly can gradually work sensor clips loose until both sensors detach. Inspect the blower for balance issues in addition to reattaching the sensors.

  4. 04

    Damaged or broken sensor leads

    Part replacement

    If the sensor wiring is kinked, pinched, or the sensor body is cracked, the thermistor may have physically separated from its mounting point. A damaged sensor will need to be replaced rather than simply reattached.

  5. 05

    Improper original installation

    Wiring / connection

    In some cases, sensors may not have been correctly seated during initial installation, and normal operation eventually causes them to fall free. Verify that both sensors are mounted to the correct positions on the inlet and outlet refrigerant lines.

See the test procedure for each cause

Frequently asked questions about sx

What does sx mean on a Samsung air conditioner?
The sx error code on a Samsung air conditioner means that both the EVAP IN and EVAP OUT temperature sensors on a specific indoor unit (identified by the number in place of "x") have simultaneously become detached from their mounting positions on the evaporator coil. The system cannot monitor evaporator temperatures without these sensors in place, so it shuts down that unit and displays the fault. The fix typically involves physically reattaching both sensors to the correct locations on the refrigerant tubing.
Can I fix the sx error code myself?
If you are comfortable opening the indoor unit's front panel and accessing the evaporator coil area, you may be able to locate and reattach the loose sensors yourself without specialized tools. However, if the sensor leads are damaged or the clips are broken, replacement parts will be needed. For multi-unit or ducted systems, it is generally recommended to have a qualified technician perform the repair to ensure both sensors are mounted to the correct points on the inlet and outlet lines.
Is it safe to keep running the air conditioner with the sx error code?
Operating the affected indoor unit while the sx error is active is not recommended. Without valid readings from both evaporator sensors, the system cannot properly regulate refrigerant flow or detect conditions like freezing or overheating on that evaporator coil. Continued operation could lead to coil freeze-up or compressor damage. Other indoor units in the system may continue to operate normally while the fault is isolated to the affected unit.
Will resetting the system clear the sx error code?
A simple power reset will not permanently clear the sx error if the sensors remain physically detached. The control board will detect the missing sensor inputs as soon as it powers up and display the fault again. The error will only clear once both sensors are properly reattached to the evaporator coil and the system confirms it is receiving valid temperature data from both thermistors.
How much does it cost to repair the sx error code on a Samsung air conditioner?
If the sensors only need to be reattached with no parts required, a service call may range from roughly $75 to $150 depending on your location and the technician's rates. If one or both sensors are physically damaged and need replacement, parts costs could add another $20 to $80 per sensor on top of the labor. Multi-unit or commercial systems where accessing the specific indoor unit is more involved may carry higher labor costs.

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