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Error code reference

U-Line Ice Maker Error Code Temp Hi 12H+

Zone temperature is more than 10°F over set point for over 12 hours.

U-Line codesU-Line ice maker codes

Zone temperature is more than 10°F over set point for over 12 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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  • Step-by-step tests with expected resistance, voltage, and continuity values
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What Temp Hi 12H+ means on a U-Line ice maker

The Temp Hi 12H+ error code on a U-Line ice maker indicates that the temperature in the monitored zone has remained more than 10°F above the configured set point for a continuous period exceeding 12 hours. This is not a momentary spike or transient condition. The 12-hour threshold means the unit has been unable to maintain adequate cooling for an extended period, pointing to a substantive failure in the refrigeration or air circulation system rather than a brief door-open event or ambient temperature fluctuation.

The primary systems implicated by this fault are the compressor, the evaporator fan, and the associated relay circuitry and DC control outputs that drive them. The compressor is responsible for circulating refrigerant and generating the cooling effect, while the evaporator fan moves air across the evaporator coil to transfer that cooling into the storage zone. If either component fails, or if the relay or DC output signal controlling them is faulty, the unit loses its ability to pull the zone temperature down to the set point. A failed relay can prevent the compressor or fan motor from receiving the voltage needed to operate, even if the components themselves are mechanically sound.

Diagnosis should begin with confirming whether the compressor and evaporator fan are actually running. Listen and feel for compressor vibration, and check that the evaporator fan is spinning. From there, testing the relevant relays and measuring the DC output signals from the control board will identify whether the fault is electrical or mechanical. Refrigerant loss, a seized compressor, a burned fan motor, or a failed control board output are all potential root causes that can produce this sustained high-temperature condition.

Source: manufacturer service documentation.

Common causes of Temp Hi 12H+

  1. 01

    Compressor failure

    Part replacement

    A seized, burned-out, or electrically open compressor will prevent the refrigeration cycle from running entirely. Confirm the compressor is receiving voltage and check for unusual heat, noise, or complete silence at the compressor body.

  2. 02

    Evaporator fan motor failure

    Part replacement

    If the evaporator fan motor has burned out or seized, cold air cannot be distributed through the zone even if the compressor is operating. Check that the fan blade spins freely and that the motor receives its DC operating voltage.

  3. 03

    Faulty relay or DC control output

    Part replacement

    The relays and DC outputs on the control board switch power to the compressor and fan motor. A failed relay or a dead DC output channel can cut power to these components without any mechanical failure in the components themselves. Test relay coil resistance and switching function, and verify DC output signal levels from the board.

  4. 04

    Refrigerant loss

    Part replacement

    A refrigerant leak reduces the system's ability to absorb heat, causing the zone temperature to rise gradually over time. Signs include ice buildup in unusual locations, an unusually warm evaporator coil, or a compressor that runs continuously without cooling the zone.

  5. 05

    Blocked airflow or condenser

    Wiring / connection

    Heavy dust or debris buildup on the condenser coil, or an obstruction blocking air circulation around the unit, can prevent adequate heat rejection and cause the zone temperature to rise. Inspect and clean the condenser coil and verify the unit has proper clearance on all sides.

See the test procedure for each cause

Frequently asked questions about Temp Hi 12H+

What does Temp Hi 12H+ mean on a U-Line ice maker?
This code means the temperature inside the ice maker zone has been more than 10°F above the set point for over 12 hours continuously. It indicates a sustained cooling failure rather than a brief temperature spike. The compressor, evaporator fan, or the relays and DC outputs controlling them are the primary areas to investigate.
Can I fix the Temp Hi 12H+ error myself?
Some causes, such as a blocked condenser coil or restricted airflow, can be addressed without professional help by cleaning the condenser and ensuring the unit has proper clearance. However, diagnosing and replacing a failed compressor, evaporator fan motor, or control board relay typically requires electrical testing tools and comfort working with appliance electronics. Refrigerant issues must be handled by a certified technician.
Will resetting the unit clear the Temp Hi 12H+ error?
A power reset may clear the displayed code temporarily, but the error will return if the underlying cause has not been corrected. Because the fault requires more than 12 hours of sustained over-temperature conditions to trigger, it reflects a real mechanical or electrical problem that a reset alone will not resolve. Always diagnose and repair the root cause before relying on a reset.
Is it safe to use my U-Line ice maker while the Temp Hi 12H+ code is active?
No. If the zone has been more than 10°F above set point for over 12 hours, the unit is not maintaining proper temperatures for ice production or storage. Ice produced or stored under these conditions may not meet safe temperature standards. The unit should be taken out of service until the fault is diagnosed and repaired.
How much does it cost to repair a U-Line ice maker showing the Temp Hi 12H+ error?
Repair costs depend on which component has failed. Cleaning a blocked condenser may cost little to nothing if done yourself. Replacing an evaporator fan motor or relay typically falls in the range of $100 to $300 including parts and labor. A compressor replacement is the most expensive scenario, often ranging from $400 to $800 or more depending on the model and local labor rates. A refrigerant repair adds leak detection and recharge costs on top of any parts needed.

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