- Appliances
- Refrigerators
Er FU
LG Er FU on a refrigerator: freezer not getting cold
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
LG says FU is a freezer cycle error: 10 minutes after starting, it has not dropped below 3.5 °C. Unplug it for 60 seconds, plug it straight into the outlet and check the -18 °C setting, vents, seals and door use. Watch the food.
Safety first
Stop and check this first
- Only a certified refrigeration technician handles the compressor and refrigerant circuit. Do not open the rear compartment: there is pressurised refrigerant and mains voltage.
- With FU the freezer may be above 0 °F. Follow the CDC rule: food that still has ice crystals or is at 40 °F or below can be refrozen; when in doubt, throw it out.
Safe checks you can perform
- 60 second reset and -18 °C setting
- Doors, seals and vents
- Food temperature
Leave these tasks to a qualified professional
- Do not attempt this professional task: Cooling system diagnosis by a certified technician
- Do not attempt this professional task: Temperature test after the repair
What a technician must be able to justify
A technician is coming
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Cooling system diagnosis by a certified technician
What they doA certified refrigeration technician checks the compressor operation and circuit temperatures with instruments.
They must show youthe compressor and circuit measurements against LG's specification.
In writingthe cause, the replaced part and, if the circuit is opened, the refrigerant recovered and charged.
Temperature test after the repair
What they doAfter the repair, the freezer is left running and the technician checks it reaches the -18 °C setting without FU returning.
They must show youthe freezer reading after the test.
In writingthe readings and the length of the test.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Checks and evidence, step by step
Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
- 1
60 second reset and -18 °C setting
No special tools
Procedure
- Who:
- you.
- How:
- unplug the fridge for 60 seconds, plug it straight into the wall outlet and check on the panel that the freezer is set to -18 °C, as LG instructs.
- Result that matters:
- the setting is correct and FU does not return.
- If the setting was different:
- correct it and see whether the temperature drops.
- If the setting was correct and FU returns:
- move on to the doors and vents.
- Evidence to keep:
- a photo of the setting and the code.
Evidence: [LG Refrigerator] Digital and Analog Error Codes
- 2
Doors, seals and vents
No special tools
Procedure
- Who:
- you.
- How:
- check that the seals are not damaged and close properly, that the doors are not opened very often and that no food blocks the air vents.
- Result that matters:
- the cold is not escaping or blocked, as LG asks you to check.
- If you find a damaged seal or blocked vents:
- fix it and see whether the temperature drops.
- If everything is fine:
- the cause is inside the cooling system; request service.
- Evidence to keep:
- photos of the seals and vents.
Evidence: [LG Refrigerator] Digital and Analog Error Codes
- 3
Food temperature
No special tools
Procedure
- Who:
- you.
- How:
- put an appliance thermometer in the fridge and another in the freezer, and keep the doors closed while the freezer gets back to temperature.
- Result that matters:
- the CDC sets 40 °F (about 4 °C) or below in the fridge and 0 °F (about -18 °C) or below in the freezer.
- If the readings are within range:
- the food is still protected; check the thermometers again every few hours.
- If the fridge is above 40 °F:
- with the door closed, the CDC gives the fridge 4 hours at most and a full freezer 48 hours (24 if half full). Frozen food that still has ice crystals or is at 40 °F or below can be refrozen. When in doubt, throw it out without tasting it.
- Evidence to keep:
- a photo of each thermometer with the time and a list of what you threw away.
Evidence: Keep Food Safe After a Disaster or Emergency
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Appliances
- Brand
- LG
- Product type
- Refrigerators
Known code variants
- E FU
- ER FU
- Er(E) FU
- Error FU LG
- FU
- FU congelador LG
- LG freezer FU
- LG FU error
What it means
LG defines FU as a freezer compartment cycle fault: after 10 minutes of running, the freezer temperature has not dropped below 3.5 °C. Its guide asks you to unplug for 60 seconds and plug straight into the outlet, check that the compressor runs, that the freezer is set to -18 °C, how often the doors are opened, that the vents are not blocked, and the condition of the door seals and insulation. The code says the cold is not getting through, not what blocks it: anything from a door not closing to a cooling circuit problem.
Warnings and stop conditions
- Higheditorial warning
Only a certified refrigeration technician handles the compressor and refrigerant circuit. Do not open the rear compartment: there is pressurised refrigerant and mains voltage.
Evidence: [LG Refrigerator] Digital and Analog Error Codes
- Highsource verified
With FU the freezer may be above 0 °F. Follow the CDC rule: food that still has ice crystals or is at 40 °F or below can be refrozen; when in doubt, throw it out.
Evidence: Keep Food Safe After a Disaster or Emergency
Symptoms and causes
Probable causes · in order
- Warm air getting in through doors or sealsPossible
LG asks you to check frequent door opening, seals and door insulation. It fits if you find a damaged seal or a door that does not close.
Evidence: [LG Refrigerator] Digital and Analog Error Codes
- Blocked air vents or wrong settingPossible
LG asks you to check the vents and that the freezer is set to -18 °C. It is confirmed if the temperature drops once you clear them or correct the setting.
Evidence: [LG Refrigerator] Digital and Analog Error Codes
- Compressor or cooling circuit not coolingPossible
LG asks you to check that the compressor runs. If doors, vents and setting are fine and FU stays, diagnosis belongs to a certified refrigeration technician.
Evidence: [LG Refrigerator] Digital and Analog Error Codes
Virtual technician
Does Er FU still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
[LG Refrigerator] Digital and Analog Error Codes
LG Electronics · 2025 · official_doc
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