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Error code reference

Dacor Range Oven Cooktop Error Code U20

Over temperature (upper/single oven)

Dacor codesDacor range oven cooktop codes

Over temperature (upper/single oven) - cook temp over 610°F for 2 minutes.

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
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What U20 means on a Dacor range oven cooktop

The U20 error code on a Dacor range or oven indicates an over-temperature condition in the upper or single oven cavity. Specifically, the control board has detected that the cook temperature has exceeded 610°F and remained above that threshold for a continuous period of two minutes. This is a protective fault designed to prevent damage to the oven cavity, internal components, and surrounding cabinetry. When this condition is met, the control shuts down the heating system and displays the U20 code to alert the user and technician.

The primary components involved in this fault are the oven temperature sensor (RTD probe), the relay board or control board that drives the bake and broil elements, and the heating elements themselves. A runaway temperature condition typically occurs when the control board loses accurate feedback from the temperature sensor, causing it to continue supplying power to the elements without regulating output. It can also result from a shorted or stuck relay on the relay board that keeps an element energized regardless of control commands.

A failed or out-of-calibration temperature sensor is among the most frequent contributors, as a sensor reading lower than actual temperature will cause the control to compensate by driving the elements harder. A defective control board or relay board with a welded relay contact is another serious possibility. In rare cases, using the oven at maximum broil settings for extended periods without adequate ventilation can contribute to the condition, though true component failures are the more common root cause.

Source: manufacturer service documentation.

Common causes of U20

  1. 01

    Faulty oven temperature sensor

    Part replacement

    A failed or drifting RTD temperature sensor can report a lower temperature than what actually exists in the cavity, causing the control board to keep heating beyond safe limits. Check the sensor resistance at room temperature, a healthy sensor typically reads around 1080 ohms at 75°F, and inspect for physical damage or corrosion at the connector.

  2. 02

    Stuck or shorted relay on relay board

    Part replacement

    A welded relay contact on the relay board can keep the bake or broil element continuously energized even when the control board sends a shutoff signal. This results in uncontrolled temperature rise and will trigger U20 regardless of the sensor reading.

  3. 03

    Defective control board

    Part replacement

    The main control board regulates power to the heating elements based on sensor feedback. Internal failures on the board can cause it to output continuous power or misinterpret sensor signals, leading to a runaway temperature condition.

  4. 04

    Damaged or shorted temperature sensor wiring

    Wiring / connection

    Wiring harness damage between the temperature sensor and the control board, including pinched, burnt, or shorted wires, can cause incorrect resistance readings that mimic a cool oven and drive the control to overheat the cavity.

  5. 05

    Broil element shorted to ground

    Part replacement

    A broil element that has developed an internal short can draw excessive current and generate more heat than the control board intends. Inspect the element for visible burn marks, blistering, or holes and test for continuity to ground.

See the test procedure for each cause

Frequently asked questions about U20

What does U20 mean on a Dacor range, oven, cooktop?
The U20 code means the oven detected a cook temperature exceeding 610 degrees Fahrenheit sustained for two or more minutes in the upper or single oven cavity. This is a safety-triggered shutdown to protect the appliance and surrounding structure. The oven will stop heating until the fault is cleared and the underlying cause is corrected.
Is it safe to use my Dacor oven while the U20 code is displayed?
No, you should not attempt to continue cooking while U20 is active. The code indicates the oven reached a dangerously high temperature and shut down as a protective measure. Operating it again before diagnosing the root cause risks damaging the oven cavity, surrounding cabinetry, and could create a fire hazard.
Will resetting the Dacor oven clear the U20 error code?
Disconnecting power to the oven for a few minutes may clear the code temporarily and allow the oven to restart, but if the underlying component failure is still present, U20 will return once the oven reaches operating temperature again. A reset is useful for confirming whether the fault is intermittent, but it is not a repair.
How do I fix a U20 error on my Dacor oven?
Start by testing the oven temperature sensor for correct resistance and inspecting its wiring harness for damage. If the sensor checks out, examine the relay board for signs of burnt or welded relay contacts. Depending on the failed component, you will likely need to replace the temperature sensor, relay board, or control board, all of which require disassembly of the oven.
How much does it cost to repair a Dacor oven showing U20?
Repair costs vary depending on which component has failed. A replacement temperature sensor typically ranges from around $30 to $80 for the part, while a relay board or control board can range from $150 to $400 or more depending on the model. Adding professional labor, total repair costs generally fall between $200 and $600, though complex control board replacements on higher-end models can exceed that range.

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