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Error code reference

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

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

U-Line codesU-Line ice maker codes

Right 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 R Temp Lo 6H+ means on a U-Line ice maker

The R Temp Lo 6H+ error code indicates that the right zone temperature has measured at least 10 degrees Fahrenheit below the configured set point for a continuous period exceeding 6 hours. This is a sustained low-temperature fault, meaning the unit is not simply experiencing a brief cold spike but rather a prolonged condition where the refrigeration system is either overcooling or failing to maintain the correct thermal environment. The right zone typically encompasses the ice-making compartment or a dedicated storage section, depending on the specific U-Line model configuration.

The primary suspects for this fault are the compressor, the evaporator fan, and the associated control relays and DC output signals that govern their operation. If the evaporator fan is running continuously without proper cycling, or if a relay is stuck in a position that keeps the compressor or fan energized beyond its normal duty cycle, the zone can be driven well below the set point. A failed temperature sensor could also report falsely low readings, triggering this code even if actual temperatures are within range.

Diagnosis should begin by verifying compressor operation and duty cycle, then inspecting the evaporator fan for continuous or erratic running. Check all associated relays for proper switching behavior and confirm that DC output signals from the control board are within expected parameters. Sensor resistance values should also be measured and compared against the expected temperature-to-resistance curve to rule out a faulty thermistor as the root cause before replacing mechanical components.

Source: manufacturer service documentation.

Common causes of R Temp Lo 6H+

  1. 01

    Stuck or faulty relay

    Part replacement

    A relay controlling the compressor or evaporator fan may be stuck in the closed position, keeping the component running continuously and driving zone temperatures far below the set point. Inspect each relay for proper switching and listen for audible clicking during normal cycle transitions.

  2. 02

    Evaporator fan running continuously

    Wiring / connection

    If the evaporator fan does not cycle off at the correct times, it will move cold air through the right zone without interruption, causing extended overcooling. Check the fan motor and its DC output signal to confirm it is receiving proper on/off commands from the control board.

  3. 03

    Control board DC output fault

    Part replacement

    The control board may be sending incorrect DC output signals to the compressor or fan, preventing normal cycling. Measure the DC outputs at the board terminals and compare against expected values to determine if the board is commanding components incorrectly.

  4. 04

    Faulty temperature sensor or thermistor

    Part replacement

    A defective thermistor in the right zone may report temperatures that are significantly lower than actual conditions, causing the unit to log this fault without a true overcooling event. Measure sensor resistance and cross-reference it against the expected resistance curve for the ambient temperature.

  5. 05

    Compressor not cycling off properly

    Wiring / connection

    A compressor that fails to shut down at the end of its cooling cycle will continuously drive down zone temperature. Verify that the compressor is receiving proper stop signals and that run times align with expected duty cycles for the set point.

See the test procedure for each cause

Frequently asked questions about R Temp Lo 6H+

What does R Temp Lo 6H+ mean on a U-Line ice_maker?
This code means the right zone of the ice maker has been running at least 10 degrees below the programmed set point for more than 6 consecutive hours. The unit logs this as a sustained overcooling fault to flag a problem with the refrigeration cycle, fan operation, or temperature sensing. It requires hands-on diagnosis of the compressor, evaporator fan, relays, and DC control outputs.
Can I fix the R Temp Lo 6H+ error myself on my U-Line ice maker?
Some diagnostic steps, such as visually inspecting the evaporator fan for continuous running or checking whether the unit is cycling normally, are accessible to a knowledgeable DIYer. However, testing relays, measuring DC output signals from the control board, and evaluating compressor operation typically require a multimeter and familiarity with refrigeration controls. If those checks point to a failed relay or control board, a qualified appliance technician should handle the repair.
Is it safe to keep using my U-Line ice maker while the R Temp Lo 6H+ code is active?
Continued use during an active overcooling fault is not recommended. Running the right zone significantly below its set point for extended periods can affect ice quality and may place unnecessary stress on the compressor and other refrigeration components. It is best to address the fault before relying on the unit for normal ice production.
How much will it cost to repair the R Temp Lo 6H+ error on a U-Line ice maker?
Repair costs vary depending on which component is at fault. Replacing a single relay is generally a lower-cost repair, typically ranging from around $50 to $150 including parts and labor. A control board replacement can range from $200 to $500 or more. Compressor replacement is the most expensive possibility and can exceed $400 to $700 with labor. Getting a diagnostic assessment first will help narrow down the cost before committing to a repair.
Will resetting my U-Line ice maker clear the R Temp Lo 6H+ error code?
A reset may temporarily clear the error code from the display, but it will not resolve the underlying condition causing the sustained overcooling. If the compressor, fan, or relay issue is still present, the unit will log the fault again once the 6-hour threshold is exceeded. The fault should be diagnosed and repaired rather than simply reset.

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