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Error code reference

U-Line Refrigerator Error Code L Temp Lo 6H+

Left Zone temperature is -10° under set point for over 6 hours.

U-Line codesU-Line refrigerator codes

Left Zone temperature is -10° under set point for over 6 hours.

First step from the service manual

Inspect main control for proper relay operation.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What L Temp Lo 6H+ means on a U-Line refrigerator

The L Temp Lo 6H+ error code on a U-Line refrigerator indicates that the left zone temperature has been reading 10 degrees Fahrenheit below the user-configured set point for a continuous period exceeding six hours. This is a sustained over-cooling fault, meaning the refrigeration system in the left zone is not cycling off correctly or is running with excessive capacity. The code is designed to catch prolonged thermal deviation rather than brief fluctuations, which distinguishes it from short-duration temperature alarms.

The primary diagnostic focus is the main control board, specifically the relay responsible for governing the compressor or cooling circuit in the left zone. If a relay on the control board is stuck in the closed position, the cooling system will run continuously without the normal off-cycle, driving temperatures far below the set point. A relay stuck closed would produce exactly this pattern: extended, uninterrupted cooling with no recovery toward the set point.

Beyond the relay, other contributors include a faulty thermistor providing incorrect temperature readings to the control board, a defrost system that has failed to cycle properly, or a refrigerant circuit issue causing abnormally high cooling output. However, since the first diagnostic step points directly to the main control board relay operation, relay failure or control board malfunction should be ruled out before investigating other components.

Source: manufacturer service documentation.

Common causes of L Temp Lo 6H+

  1. 01

    Main Control Board Relay Stuck Closed

    Part replacement

    A relay on the main control board that is stuck in the closed position will keep the cooling system running continuously, causing the left zone to drop well below the set point. Inspecting the relay for proper switching operation is the recommended first step.

  2. 02

    Faulty Left Zone Thermistor

    Part replacement

    If the thermistor monitoring the left zone is reading incorrectly, the control board may believe the compartment is warmer than it actually is and continue calling for cooling. A resistance check on the thermistor can confirm whether it is within the expected range for the current temperature.

  3. 03

    Defrost System Failure

    Part replacement

    A defrost system that is not initiating or completing its cycle can indirectly cause temperature extremes, particularly if the control logic is compensating by running the cooling circuit longer than intended.

  4. 04

    Refrigerant System Overcharge or Metering Issue

    Part replacement

    An overcharged refrigerant circuit or a restriction in the metering device can cause abnormally aggressive cooling in one zone, pushing temperatures significantly below set point regardless of control board commands.

  5. 05

    Incorrect Set Point Configuration

    Wiring / connection

    In rare cases, user settings or a control board that has lost its configuration may produce a set point that does not reflect the actual intended temperature, making the 10-degree deviation appear larger than it is. Verifying and resetting the set point is a quick check before deeper diagnostics.

See the test procedure for each cause

Frequently asked questions about L Temp Lo 6H+

What does L Temp Lo 6H+ mean on a U-Line refrigerator?
The L Temp Lo 6H+ code means the left zone of your U-Line refrigerator has been running 10 degrees below the configured set point for more than six hours. It indicates the cooling system is overcooling in the left compartment without cycling off as it should. This is a sustained fault rather than a momentary dip, and it typically points to a control board relay issue, a faulty thermistor, or a problem in the refrigeration circuit.
Can I fix the L Temp Lo 6H+ error myself?
Some basic checks, such as verifying the set point and confirming the thermistor connections are secure, can be performed without specialized tools. However, diagnosing a stuck relay on the main control board or checking the refrigerant system requires technical knowledge and proper equipment. If the control board relay is faulty, replacing the board is generally necessary and is best handled by a qualified technician.
Will resetting the refrigerator clear the L Temp Lo 6H+ error?
Resetting the unit may temporarily clear the error code from the display, but it will return if the underlying cause is not corrected. Because this fault requires a sustained 6-hour overcooling condition to trigger, simply resetting without addressing the faulty relay, thermistor, or other component will result in the code reappearing. A reset is useful only as part of a diagnostic process, not as a repair.
Is it safe to keep using my U-Line refrigerator while this error is active?
Continued operation with this fault active is not recommended. Temperatures 10 degrees or more below the set point can freeze items in a refrigeration zone that should remain above freezing, potentially damaging food or beverages. Additionally, running the compressor without proper cycling places extra stress on the system and could lead to further component failure.
How much does it cost to repair the L Temp Lo 6H+ error on a U-Line refrigerator?
Repair costs vary depending on the root cause. If the main control board needs replacement, parts and labor typically range from $200 to $500 or more depending on the specific model and local labor rates. A thermistor replacement is generally less expensive, often falling in the $75 to $200 range including labor. Refrigerant system repairs tend to be at the higher end of cost estimates and require a certified technician.

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