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Error code reference

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

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

U-Line codesU-Line refrigerator codes

Right 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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  • Wiring diagram references and connector pinouts from the OEM service manual
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What R Temp Lo 6H+ means on a U-Line refrigerator

The R Temp Lo 6H+ error code on a U-Line refrigerator indicates that the right zone temperature has dropped to 10 degrees Fahrenheit or more below the user-configured set point, and this condition has persisted for more than 6 continuous hours. This is not a momentary temperature fluctuation but a sustained over-cooling event, which points to a failure in the system's ability to regulate refrigerant flow or compressor cycling in the right zone. The control board monitors thermistor readings continuously and triggers this alert only after the threshold has been exceeded for the full 6-hour window.

The primary diagnostic focus should be on the main control board, specifically its relay operation. The relays on the control board govern power delivery to components such as the compressor, fans, and damper or valve assemblies. If a relay is stuck in the closed position, it can cause a component to run continuously rather than cycling on and off as needed. In the case of over-cooling, a relay stuck closed could be holding the compressor or a motorized damper open beyond the normal operating cycle, driving temperatures well below the set point.

Additional causes can include a faulty thermistor providing inaccurate temperature readings to the control board, a malfunctioning damper or thermostatic expansion valve that is not restricting refrigerant or airflow properly, or wiring issues causing incorrect signals to reach the control board. Because the fault must persist for over 6 hours before triggering, intermittent issues are less likely culprits than component failures that result in continuous over-cooling.

Source: manufacturer service documentation.

Common causes of R Temp Lo 6H+

  1. 01

    Stuck relay on main control board

    Part replacement

    A relay on the control board may be stuck in the closed position, causing the compressor or a damper to run continuously without cycling off. This is the first component to inspect, as it directly prevents normal temperature regulation.

  2. 02

    Faulty right zone thermistor

    Part replacement

    If the thermistor measuring the right zone temperature is reading colder than actual conditions, the control board may be satisfied and not taking corrective action, or conversely may be driving cooling based on incorrect data. Check the thermistor resistance values against the specification for the unit.

  3. 03

    Damper or air baffle stuck open

    Part replacement

    A motorized damper that is stuck in the open position will allow unrestricted cold airflow into the right zone, causing temperatures to drop well below the set point. Inspect the damper for physical obstruction, ice buildup, or motor failure.

  4. 04

    Thermostatic expansion valve malfunction

    Part replacement

    A TXV that is not properly restricting refrigerant flow can allow excessive refrigerant into the evaporator, resulting in continuous over-cooling. This is typically accompanied by other refrigeration symptoms such as frost buildup.

  5. 05

    Wiring or connector fault

    Wiring / connection

    Damaged wiring or a loose connector between the thermistor, damper motor, or control board can send incorrect signals that prevent the system from recognizing when the set point has been reached. Inspect harness connections for corrosion, pinching, or intermittent contact.

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 refrigerator?
This code means the right zone of your U-Line refrigerator has been running at least 10 degrees below your selected set point for more than 6 consecutive hours. It indicates a sustained over-cooling condition rather than a brief temperature swing. The most common cause is a relay on the main control board that is stuck closed, keeping a cooling component running longer than it should.
How do I fix the R Temp Lo 6H+ error on my U-Line refrigerator?
Start by inspecting the main control board for proper relay operation, as a stuck relay is the leading cause of this fault. If the relays appear functional, check the right zone thermistor for accurate resistance readings, inspect the damper for physical or mechanical issues, and examine all associated wiring for damage. Depending on the root cause, repairs may involve replacing the control board, thermistor, or damper assembly.
Will resetting my U-Line refrigerator clear the R Temp Lo 6H+ error?
A reset may temporarily clear the error code from the display, but it will not resolve the underlying component failure causing the over-cooling. If the faulty part, such as a stuck relay or damaged thermistor, is not repaired or replaced, the condition will continue and the code will return. A reset is useful for confirming whether the fault is persistent or intermittent, but it is not a repair.
Is the R Temp Lo 6H+ error a safety concern?
Excessive cooling in the right zone can damage temperature-sensitive food or beverages stored there, particularly items that should not freeze. While the refrigerator itself is not in immediate danger from this fault, prolonged operation in this state can stress the compressor and other refrigeration components. Addressing the error promptly helps avoid food loss and potential secondary component damage.
How much does it cost to repair the R Temp Lo 6H+ error on a U-Line refrigerator?
Repair costs vary depending on which component has failed. A thermistor replacement is generally on the lower end of the cost range, typically between $75 and $200 including labor. Control board replacement tends to be more expensive, often ranging from $200 to $500 or more depending on the specific model and labor rates in your area. Getting a diagnostic assessment from a qualified technician before purchasing parts is recommended.

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