Samsung Heat Pump Error Code E108

E108 indicates an open or short circuit fault in the compressor 1 sump temperature sensor. This sensor monitors temperature at the base of the compressor using a resistive thermistor. When the control board cannot read a valid resistance value from the sensor, it logs E108 and may limit compressor operation to protect the unit from running without reliable temperature feedback.

Running the heat pump continuously with E108 active is not recommended. The sump temperature sensor is a protective component, and without a valid reading the control board cannot confirm safe compressor operating conditions. Continued operation risks compressor damage. Turn off the unit and arrange for diagnosis before resuming normal use.

Repair costs vary depending on the root cause. If only the sump temperature sensor needs replacement, parts and labor typically range from around $100 to $250. If the wiring harness requires repair or replacement, costs can increase to roughly $150 to $350. A control PCB replacement is the most expensive scenario, often ranging from $300 to $600 or more depending on the specific unit model and labor rates in your area.

A knowledgeable DIYer can perform initial checks such as inspecting the sensor connector at the PCB for secure attachment and checking for visible wiring damage. However, measuring sensor resistance and comparing it to a temperature table requires a multimeter and familiarity with the component layout. Replacing the sensor or PCB typically requires accessing refrigerant-side components, which in many regions must be performed by a certified technician.

A power reset may temporarily clear the fault display, but E108 will return if the underlying sensor or wiring issue has not been corrected. Because the fault is hardware-based, the control board will re-detect the open or short circuit condition on the next startup cycle. A reset alone is not a repair and should not be used as a substitute for proper diagnosis.