Error Code COMP-UNDER-VOLTAGE
Supply voltage to compressor is too low
Moderate
Address soon - your appliance may not work properly
Also displayed as: F and R blink — Under Voltage pattern
What This Means
Low input supply voltage (below AC 53V measured at inverter for 120V models); Shorted DC link resistor R312 on inverter PCB; Weak power supply or extension cord voltage drop; Loose power cord or wall outlet issue
What actually causes this:
The voltage coming into the refrigerator dropped too low — possibly a house wiring problem, overloaded circuit, or extension cord.
First Thing to Check
Measure the wall outlet voltage with a multimeter — it should read 110–120V. Try a different outlet on a different circuit.
Parts Involved
How to Fix
- 1
Check input voltage at wall outlet with a multimeter — should be 110–127V AC (North America)
- 2
Check PCB bottom side solder joints on DC link resistors
- 3
Check R312 on inverter PCB for short
- 4
Ensure refrigerator is plugged into a dedicated outlet
This Error Applies To
Samsung RF28T5 Series Refrigerators (2020) (2020–present)
Related Error Codes
Refrigerator compartment temperature sensor is disconnected or dead
Internal humidity sensor has failed or is disconnected
Defrost sensor on freezer evaporator is failed or disconnected
Freezer fan motor is not running or not sending feedback
Supply voltage to compressor is too high
Freezer temperature sensor is failing or disconnected
Ice maker temperature sensor in freezer is failed or unplugged
External room temperature sensor is failed or disconnected