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Error code reference

U-Line Refrigerator Error Code Temp Lo 6H+

Zone temperature is more than 10°F under set point for over 6 hours.

U-Line codesU-Line refrigerator codes

Zone temperature is more than 10°F under set point for over 6 hours.

First step from the service manual

Verify thermistor connections are clean and dry. Verify thermistor resistance. Verify correct operation of zone valve.

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

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

The Temp Lo 6H+ error code on a U-Line refrigerator indicates that the temperature within a specific zone has dropped more than 10°F below the user-defined set point and has remained in that condition for longer than six consecutive hours. This is a sustained low-temperature fault, meaning brief temperature dips from normal door cycling or defrost recovery will not trigger it. The unit's control board monitors zone temperature continuously through a thermistor, and when the deviation persists beyond the six-hour threshold, the fault is logged and displayed.

The thermistor is the primary sensor responsible for reporting zone temperature to the control board. If the thermistor has a faulty connection, moisture intrusion at the connector, or has drifted out of its correct resistance range, the control board may receive a signal that reads artificially low, causing it to interpret a normal temperature as severely under set point. In multi-zone U-Line models, a zone valve controls refrigerant or airflow routing to individual compartments. A zone valve that is stuck open or not cycling correctly can allow excessive cooling in one zone, driving temperatures well below the set point and triggering this fault.

Diagnosis should begin by inspecting the thermistor wiring harness and connector for corrosion, moisture, or loose pins, then measuring the thermistor resistance and comparing it to the expected value for the current zone temperature. Next, verify that the zone valve is receiving the correct signal from the control board and is opening and closing as commanded. Both a faulty thermistor and a malfunctioning zone valve can independently produce this code, so systematic component testing is necessary to isolate the root cause.

Source: manufacturer service documentation.

Common causes of Temp Lo 6H+

  1. 01

    Faulty or drifted thermistor

    Part replacement

    A thermistor that has shifted out of its correct resistance range will send an inaccurate temperature signal to the control board, making the zone appear colder than it actually is. Measure the thermistor resistance and compare it to the expected value for the ambient zone temperature to confirm.

  2. 02

    Corroded or loose thermistor connector

    Wiring / connection

    Moisture or corrosion at the thermistor wiring connector can cause resistance to spike or signal to drop, mimicking an extremely low temperature reading. Inspect the connector for oxidation, dampness, or pins that are not fully seated.

  3. 03

    Zone valve stuck open or malfunctioning

    Part replacement

    A zone valve that fails in the open position continuously routes maximum cooling to that zone, causing temperatures to fall well below the set point. Verify the valve is receiving the correct control signal and confirm it opens and closes at the appropriate times.

  4. 04

    Control board sending incorrect signal to zone valve

    Part replacement

    If the control board is not properly commanding the zone valve to close, the valve may remain open and over-cool the zone even though the valve itself is functional. This is typically identified after confirming the valve and thermistor test within normal parameters.

  5. 05

    Ambient temperature or installation conditions

    Wiring / connection

    Unusually cold ambient conditions around the unit, such as installation in an unheated garage during winter, can contribute to excessive zone cooling. Check that the unit is installed within its rated ambient temperature range.

See the test procedure for each cause

Frequently asked questions about Temp Lo 6H+

What does Temp Lo 6H+ mean on a U-Line refrigerator?
This code means that a specific zone inside your U-Line refrigerator has been running more than 10 degrees Fahrenheit below your set point temperature for over six consecutive hours. The control board monitors zone temperature through a thermistor and flags this fault when the sustained low-temperature condition exceeds the six-hour threshold. The most likely causes are a faulty thermistor, a bad thermistor connection, or a zone valve that is not cycling correctly.
Can I fix the Temp Lo 6H+ error myself?
Some steps are DIY-friendly, such as inspecting the thermistor wiring connector for corrosion or moisture and cleaning or reseating it. Testing thermistor resistance with a multimeter is also within reach for a knowledgeable DIYer if you have the correct resistance specifications for your model. However, diagnosing and replacing a zone valve or control board typically requires more advanced technical skill and specialized tools, so professional service is recommended for those components.
Is my food safe when the Temp Lo 6H+ code is active?
Because this fault indicates the zone is running colder than set, not warmer, refrigerated items are unlikely to spoil due to the error itself. However, if the zone temperature has dropped far enough, items like fresh produce, beverages, or dairy could be at risk of freezing and being damaged. Check the actual contents of the affected zone and remove anything that should not be frozen while you address the fault.
Will resetting the refrigerator clear the Temp Lo 6H+ error?
A power reset may temporarily clear the displayed code, but if the underlying cause, such as a faulty thermistor or malfunctioning zone valve, is still present, the unit will detect the condition again and the code will return after another six hours. Clearing the code without fixing the root cause does not resolve the problem. A proper repair requires diagnosing and correcting the defective component.
How much does it cost to repair a U-Line refrigerator showing Temp Lo 6H+?
Repair costs vary depending on which component is at fault. Thermistor replacement is typically the least expensive fix, with parts generally ranging from around 20 to 60 dollars plus labor. Zone valve replacement tends to run higher, with parts in the range of 50 to 150 dollars or more depending on the model. If a control board is involved, costs can increase significantly. A diagnostic service call from a qualified technician will give you a firm estimate for your specific situation.

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