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Error code reference

LG Heat Pump Error Code E184

Change of EVAP OUT temperature of other indoor unit during the piping check.

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What the E184 error code actually means

Your LG heat pump ran a self-test to confirm that the refrigerant pipes are connected correctly, and it found that one of the indoor units was showing unexpected temperature changes when it should not have been. This usually means the refrigerant pipes may be connected to the wrong units, or there could be a sensor problem. A technician will need to trace the refrigerant lines and verify that every indoor unit is connected properly.

Diagnostic procedure

The full E184 procedure

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1
First diagnostic step
Check piping connections between indoor units and MCU.
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Most common causes of E184

Ranked by how often they cause this code
  1. 1Cross-connected refrigerant piping between indoor units
  2. 2Incorrect branch connection at the MCU manifold
  3. 3Faulty EVAP OUT thermistor on the affected indoor unit
  4. 4Loose or damaged thermistor wiring connections
  5. 5MCU communication or mapping configuration error

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Questions people ask about E184

What does E184 mean on a LG heat pump?
E184 indicates that during the piping check routine, the evaporator outlet temperature of a secondary indoor unit changed when it was not expected to. This tells the system that refrigerant may be flowing to the wrong indoor unit, which points to a piping connection problem or a sensor fault. The system flags this during the piping verification sequence to prevent operation with an incorrectly configured refrigerant circuit.
Is it safe to run my LG heat pump with an E184 error?
Operating the system with E184 active is not recommended. The error indicates a potential piping configuration problem, and running the system with incorrectly connected refrigerant lines can damage compressors, indoor units, or other components. Leave the system off until the piping connections and sensor readings have been confirmed as correct.
How much does it cost to repair an E184 error on a LG heat pump?
Repair costs vary widely depending on the cause. If the fix involves reconfiguring MCU settings or reseating a thermistor connector, service call fees alone may range from roughly 80 to 150 dollars. If refrigerant lines need to be re-routed or a thermistor needs replacement, total costs including labor and parts could range from 200 to 600 dollars or more depending on system complexity and local labor rates.
Can I fix the E184 error myself?
Some causes, such as a misconfigured MCU address setting or a loose thermistor connector, can be checked by a knowledgeable technician or experienced DIYer. However, tracing and correcting cross-connected refrigerant piping requires accessing the refrigerant circuit, which involves handling refrigerant and is a job for a certified HVAC technician. Do not attempt to modify refrigerant lines without proper certification and equipment.
Will resetting the heat pump clear the E184 error?
A simple power reset may temporarily clear the error code, but if the underlying piping connection or sensor issue is not corrected, E184 will return the next time the system runs a piping check. The piping check must complete successfully without detecting unexpected EVAP OUT temperature changes before the error is truly resolved.

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