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Error code reference

U-Line Ice Maker Error Code R Evap T Open

Right evaporator thermistor circuit is open.

U-Line codesU-Line ice maker codes

Right evaporator thermistor circuit is open.

First step from the service manual

Inspect evaporator thermistor connection. Replace if necessary.

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

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What R Evap T Open means on a U-Line ice maker

The R Evap T Open error on a U-Line ice maker indicates that the right evaporator thermistor circuit is reading as open, meaning the control board is receiving no valid signal from the thermistor. An open circuit condition occurs when electrical continuity is broken somewhere in the sensing loop, either at the thermistor itself, along the wiring harness, or at a connector. The evaporator thermistor is a temperature-sensing resistor that monitors the evaporator coil temperature and feeds that data to the control board to regulate the refrigeration and harvest cycles.

When the thermistor circuit is open, the board cannot determine the actual evaporator temperature, which prevents it from safely managing ice production. Rather than operate blindly and risk component damage, the unit triggers this fault code and typically halts the affected functions. On dual-evaporator U-Line models, the right-side thermistor monitors the right evaporator independently, so only the right-side operation is directly implicated.

The most common physical cause is a loose or corroded connector at the thermistor plug, which breaks continuity without damaging the thermistor itself. Reconnecting or cleaning the connector often resolves the fault. If the connector is secure, the thermistor itself may have failed internally, producing infinite resistance across its terminals. A functioning thermistor will show a measurable resistance value that changes with temperature. A broken wire in the harness between the thermistor and the control board is a less frequent but possible cause.

Source: manufacturer service documentation.

Common causes of R Evap T Open

  1. 01

    Loose or disconnected thermistor connector

    Wiring / connection

    The plug connecting the thermistor to the wiring harness may have vibrated loose or been inadvertently disconnected during servicing. Inspect the connector at the thermistor end and at the control board end, and reseat both firmly.

  2. 02

    Failed evaporator thermistor

    Part replacement

    The thermistor itself may have an internal open failure, producing infinite resistance regardless of temperature. Testing across the thermistor terminals with a multimeter will show no continuity or an out-of-range resistance reading if the component has failed.

  3. 03

    Corroded or damaged connector terminals

    Wiring / connection

    Moisture inside the ice maker compartment can cause corrosion at the thermistor connector pins, increasing resistance to the point of an open circuit. Look for green or white oxidation on the pins and clean or replace the connector as needed.

  4. 04

    Broken or chafed wiring harness

    Part replacement

    A wire in the harness running from the right evaporator thermistor to the control board may be broken internally or have damaged insulation causing an intermittent open. Flex the harness while monitoring resistance to identify a break.

  5. 05

    Control board input failure

    Part replacement

    In rare cases, the thermistor input circuit on the control board itself can fail, causing the board to report an open circuit even when the thermistor and wiring are intact. This is typically diagnosed after confirming the thermistor and harness test correctly.

See the test procedure for each cause

Frequently asked questions about R Evap T Open

What does R Evap T Open mean on a U-Line ice_maker?
R Evap T Open means the control board has detected an open circuit in the right evaporator thermistor loop. The thermistor is a temperature sensor mounted on the right evaporator coil, and an open circuit means the board is receiving no valid temperature signal from it. This can be caused by a loose connector, a failed thermistor, or a break in the wiring harness. The unit may stop producing ice until the fault is resolved.
How do I fix the R Evap T Open error on my U-Line ice maker?
Start by inspecting the thermistor connector at the right evaporator and at the control board, reseating any loose plugs. If the connection is secure, use a multimeter to test the thermistor resistance across its terminals. If the reading is infinite or clearly out of range, the thermistor needs to be replaced. Also inspect the wiring harness for any visible damage or breaks between the thermistor and the board.
Is it safe to continue using my U-Line ice maker while the R Evap T Open error is showing?
It is not recommended to continue running the unit with this fault active. Without a valid temperature reading from the right evaporator thermistor, the control board cannot properly manage the refrigeration and harvest cycles on that side, which could lead to incomplete ice production or potential component stress. Addressing the fault promptly helps prevent further issues.
Will resetting my U-Line ice maker clear the R Evap T Open error?
A reset may temporarily clear the displayed fault, but the error will return if the underlying open circuit condition has not been corrected. The fault is triggered by a real electrical condition, not a software glitch, so the thermistor connection, the thermistor itself, or the wiring must be inspected and repaired before the error will stay cleared.
How much does it cost to repair the R Evap T Open error on a U-Line ice maker?
If only the connector needs reseating or cleaning, there may be no parts cost, and a service call fee could range from around 75 to 150 dollars. Replacing the evaporator thermistor typically involves a modest parts cost in the range of 20 to 60 dollars plus labor. If the control board has failed, parts and labor costs can be considerably higher, often ranging from 200 to 400 dollars or more depending on the model.

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