LG Heat Pump Error Code 47

Error code 47 on an LG heat pump indicates that the discharge pipe temperature sensor on the constant speed compressor has been detected as either open or short circuit. The control board cannot get a valid temperature reading from this sensor, so it stops normal operation to protect the compressor. The fault can originate from the sensor itself, the wiring harness, or the connector at the PCB.

It is not advisable to continue running the unit with this error active. The discharge pipe sensor protects the compressor from overheating by alerting the system to abnormally high discharge temperatures. Without a reliable reading from this sensor, the heat pump cannot respond appropriately to a compressor overheat condition, which could lead to compressor damage over time.

A power reset may temporarily clear the fault code and allow the unit to restart, but if the underlying sensor, connector, or wiring problem has not been corrected, the code 47 will return once the control board polls the sensor again. A reset is useful for confirming whether the fault is intermittent, but it is not a repair. The sensor circuit should be properly diagnosed and repaired to prevent the error from recurring.

A knowledgeable DIYer can start by checking the sensor connector at the PCB for loose pins or corrosion and reseating it firmly, which resolves the fault in some cases. Testing the thermistor resistance with a multimeter is also straightforward if you are comfortable working around electrical components. However, replacing the sensor or diagnosing a faulty PCB typically requires refrigeration and electrical knowledge, so a qualified technician is recommended if basic connector checks do not clear the code.

If only the discharge pipe thermistor needs replacement, parts and labor typically range from around 80 to 200 dollars depending on your location and service rates. If the wiring harness requires repair or replacement, costs can rise to the 150 to 350 dollar range. A PCB replacement, in the unlikely event it is required, can push total repair costs into the 400 to 800 dollar range or higher.