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Error code reference

Dacor Oven Error Code L20

Lower oven over temperature

Dacor codesDacor oven codes

Lower oven over temperature - center of cell temperature over 610°F for 2 minutes during cook mode.

First step from the service manual

Verify probe readings, verify cycling/timing charts, verify calibration values to software version.

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

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What L20 means on a Dacor oven

The L20 error code on a Dacor oven indicates a lower oven over-temperature condition. Specifically, the control system has detected that the center of cell temperature has exceeded 610°F for a continuous period of 2 minutes while the oven is operating in cook mode. This is a protective fault designed to prevent damage to the oven cavity, food, and surrounding cabinetry. The "center of cell" refers to the temperature measured at the core sensing point within the lower oven cavity, typically monitored by the oven temperature probe.

The primary diagnostic path involves verifying probe readings to confirm whether the temperature sensor is accurately reporting conditions or producing an erroneous high reading. A faulty probe can report falsely elevated temperatures, triggering the fault even when actual cavity temps are within range. Technicians should also verify cycling and timing charts to assess whether the bake or broil element is cycling correctly, as a relay stuck in the closed position could cause continuous heating without proper cutoff.

Calibration values tied to the installed software version are a critical part of diagnosis. If the control board has been replaced or updated, a mismatch between calibration offset values and the current software version can cause incorrect temperature thresholds to be applied, leading to premature over-temperature faults. Confirming that the software version and calibration data are properly aligned is essential before replacing any components.

Source: manufacturer service documentation.

Common causes of L20

  1. 01

    Faulty oven temperature probe

    Part replacement

    A defective or drifting temperature probe can send inaccurate high-temperature readings to the control board, triggering the L20 fault even when actual cavity temperature is normal. Check probe resistance values against specification for the oven model.

  2. 02

    Stuck or failed heating element relay

    Part replacement

    If the relay controlling the bake or broil element is stuck closed, the element will heat continuously without cycling off, causing the oven temperature to climb beyond safe limits. Review cycling and timing charts to identify abnormal element run times.

  3. 03

    Control board calibration mismatch

    Wiring / connection

    A mismatch between the calibration offset values stored in the control board and the installed software version can cause incorrect temperature thresholds, resulting in a premature over-temperature fault. Verify that calibration values correspond to the current software version.

  4. 04

    Damaged or shorted heating element

    Part replacement

    A partially shorted bake or broil element can draw excessive power and generate more heat than intended, pushing cavity temperatures above the 610°F threshold. Inspect the element visually for burns, blistering, or breaks.

  5. 05

    Poor oven ventilation or blocked airflow

    Wiring / connection

    Restricted airflow within the oven cavity can cause heat to build up abnormally at the center sensing point, triggering the over-temperature threshold. Check for blockages around vents or improper rack positioning that could trap heat.

See the test procedure for each cause

Frequently asked questions about L20

What does L20 mean on a Dacor oven?
The L20 code means the lower oven experienced an over-temperature condition, with the center of the oven cavity exceeding 610°F for 2 or more minutes during cook mode. The oven's control system triggers this fault as a protective measure to prevent damage. It is not a code that should be ignored, as it indicates either a real overheating event or a sensor or calibration issue causing a false reading.
Is it safe to use my Dacor oven when the L20 code is displayed?
No, you should not continue using the oven while the L20 code is active. The fault indicates the oven either reached a dangerously high temperature or has a component failure that could lead to overheating. Continued use without resolving the root cause poses a risk of damage to the appliance and potentially to surrounding cabinetry or the home.
Will resetting the oven clear the L20 error code?
Power cycling the oven may temporarily clear the L20 code, but if the underlying cause is not corrected, the fault will return once the oven is used again. A reset does not fix a faulty temperature probe, a stuck relay, or a calibration mismatch. Proper diagnosis of the probe readings, element cycling behavior, and software calibration values is necessary before the oven can be safely returned to service.
How do I fix the L20 error on a Dacor oven?
Diagnosis should begin by verifying the temperature probe resistance and comparing readings against expected values for the oven model. Next, review cycling and timing charts to confirm the heating element is turning on and off correctly rather than running continuously. Finally, confirm that the calibration values stored in the control board match the installed software version, as a mismatch can cause false over-temperature faults. Depending on the cause found, repair may involve replacing the temperature probe, the control board, or a heating element.
How much does it cost to repair an L20 error on a Dacor oven?
Repair costs vary depending on the failed component. A replacement oven temperature probe typically runs in the range of $30 to $80 for parts alone. A control board replacement is considerably more expensive, often ranging from $150 to $400 or more for the part. Adding professional labor costs, total repair bills commonly fall between $150 and $500 depending on the diagnosis outcome and your location.

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