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Error code reference

U-Line Ice Maker Error Code L Temp Lo 6H+

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

U-Line codesU-Line ice maker codes

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

First step from the service manual

Check compressor, evaporator fan and related relays and DC outputs.

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 ice maker

The L Temp Lo 6H+ error code on a U-Line ice maker indicates that the left zone temperature has been reading 10 degrees or more below the configured set point for a continuous period exceeding six hours. This is a sustained thermal fault, meaning the unit is not simply experiencing a brief temperature swing but has been running significantly colder than intended for an extended duration. The left zone in a U-Line unit typically refers to the primary refrigeration or freezing compartment associated with the ice-making system, and a temperature that drops this far below set point suggests the refrigeration circuit is overcooling or the control system has lost the ability to regulate the cooling cycle properly.

The primary components to evaluate first are the compressor, the evaporator fan, and the relays and DC outputs that control them. If the compressor is running continuously without cycling off, or if a relay is stuck in a closed position, the system will continue to cool beyond the set point indefinitely. A faulty thermistor or temperature sensor in the left zone can also report an inaccurate temperature reading, causing the controller to misread actual conditions or fail to trigger a defrost or shut-off cycle. Additionally, a malfunctioning evaporator fan can disrupt airflow patterns, creating localized overcooling near the sensor.

Diagnosing this fault requires checking the DC output signals from the main control board to the compressor relay and evaporator fan motor, verifying that relays are opening and closing correctly, and confirming that the temperature sensor is reading accurately. A sensor that is out of calibration or shorted can send a falsely warm signal to the board, causing the system to run the compressor longer than necessary and push the zone temperature well below set point.

Source: manufacturer service documentation.

Common causes of L Temp Lo 6H+

  1. 01

    Stuck or faulty compressor relay

    Part replacement

    A relay that fails in the closed position keeps the compressor running continuously, preventing the zone from warming back to set point. Check DC output signals to the relay and verify the relay is opening during normal off cycles.

  2. 02

    Defective temperature sensor in the left zone

    Part replacement

    A shorted or out-of-calibration thermistor can report a falsely high temperature to the control board, causing the board to run the compressor longer than needed. Verify the sensor's resistance value matches expected specifications for the measured temperature.

  3. 03

    Control board DC output failure

    Part replacement

    If the main control board is outputting a continuous DC signal to the compressor or fan circuits without cycling, the cooling system will not shut off at the correct temperature. Measure DC outputs at the board to confirm proper on/off behavior.

  4. 04

    Evaporator fan malfunction disrupting airflow

    Part replacement

    An evaporator fan running at the wrong speed or failing intermittently can cause uneven air distribution, concentrating cold air near the temperature sensor and triggering an overcooling condition. Inspect the fan motor and verify it is operating correctly.

  5. 05

    Incorrect set point configuration

    Wiring / connection

    If the left zone set point was accidentally set too high relative to the unit's actual operating range, the system may read as persistently under-temperature without any component failure. Confirm the set point is appropriate for the intended use of the zone.

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 ice_maker?
This error means the left zone temperature has been running 10 degrees or more below the configured set point for over six hours. It indicates a sustained overcooling condition rather than a brief fluctuation. The fault is typically tied to the compressor, evaporator fan, associated relays, or the temperature sensor in the left zone.
How do I fix the L Temp Lo 6H+ error on my U-Line ice maker?
Start by inspecting the compressor, evaporator fan, and the relays and DC outputs that control them, as these are the primary components involved in this fault. Check whether the compressor is cycling on and off correctly or running continuously. If a relay is stuck or a temperature sensor is providing inaccurate readings, those components will need to be tested and likely replaced.
Will resetting my U-Line ice maker clear the L Temp Lo 6H+ error?
A reset may temporarily clear the error code, but if the underlying cause is not corrected, the fault will return once the unit has run long enough to trigger the six-hour threshold again. Resetting without diagnosing and repairing the root cause is not a reliable fix. The compressor, fan, relays, and sensor should all be evaluated before assuming the issue is resolved.
Is it safe to use my U-Line ice maker when the L Temp Lo 6H+ error is active?
When this error is active, the left zone is operating significantly outside its intended temperature range, which can affect ice quality and the integrity of any stored items. Continued operation without addressing the fault also puts additional stress on the compressor and related components. It is best to stop using the unit for ice production until the fault is diagnosed and corrected.
How much does it cost to repair a U-Line ice maker showing the L Temp Lo 6H+ error?
Repair costs vary depending on which component is at fault. Replacing a temperature sensor typically falls in the lower range of repair costs, while a failed relay, control board, or compressor will be more expensive. In general, expect to budget anywhere from $100 to $600 or more depending on parts and labor in your area. A technician can give a more precise estimate after diagnosing the specific cause.

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