XLT Pizza Oven Error Code Comm Error: Internal Controller Error
Comm Error is listed in the manual as an internal software error. The manual's step is a hard reset: unplug the oven for one minute, plug it back in and power on. If the error still exists, contact XLT.
High: the controller reports an internal error and may not respond to commands.
- Code
- Comm Error
- Maker
- XLT
- Equipment
- Pizza ovens
- Applies to
- XLT conveyor ovens, gas version H (Standard, World, Australia, Korea) with LUI/OMC controller; the electric version H Parts & Service Manual XD 9007A prints the
What does XLT Comm Error mean?
Comm Error is the alarm name shown on the LUI display, and the manual defines it only as an internal software error. It does not say which two parts of the oven were supposed to be talking, so we do not name them. The control board LEDs show the Alarm LED flashing with all other LEDs off, the same pattern as the other internal alarms such as Software Error, EEPROM Error and Key Short. That pattern tells you the controller is reporting a problem with its own operation, not with heating, the conveyor or the fan. The manual lists no causes and gives the hard reset as the single action: switch off, unplug for one minute, plug back in and power on, then contact XLT at 888-443-2751 if the error is still there. Because there is no further guidance, a technician will need to look at the controller and display connections to find the reason.
Affected models and control systems
XLT conveyor ovens, gas version H (Standard, World, Australia, Korea) with the LUI/OMC controller. The electric version H Parts & Service Manual XD 9007A prints the same table.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Comm Error alarm on the LUI display
- Alarm LED flashing with all other LEDs off
- Oven not responding to the LUI or not starting a bake
- Display going blank or restarting
Possible causes
Likely causes — what usually sits behind Comm Error on this control. A technician confirms which one it is before any part is replaced.
- Loose or damaged cable between the display and the controller board
- Controller board or display with a failed communication circuit
- Power interruption or surge that disturbed the controller
- Moisture or grease reaching a connector in the control area
Safe checks before calling for service
- Switch off the oven and unplug it for one minute, as the manual says.
- Plug it back in, power on and watch the LUI for a few minutes.
- If the oven responds normally, note the time the alarm cleared.
- If Comm Error returns, contact XLT or a service company.
- Tell the technician whether the oven lost power or was moved just before the alarm.
How a technician diagnoses Comm Error
- Read the alarm and confirm the LED pattern with only the Alarm LED flashing.
- Check the harness and plugs between the LUI and the control board for damage or looseness.
- Check the supply to the board for stability.
- Observe whether the alarm returns at power-up or after a delay.
- Replace the cable, display or board only after testing points to it.
- Harness inspection inside the control area exposes live 208-240 V wiring.
- A technician is needed to tell a cable problem from a board or display problem.
- Replacement parts must be matched to the oven and its settings.
How Comm Error differs from similar codes
The manual describes Comm Error as an internal software error, the same wording as Software Error. Software Error also lists a check for pinched wires.
Technical reference
- Document
- XLT Gas Oven & XLT Hood Parts & Service Manual (XD 9006A)
- Edition
- 01/05/2026
- Models / control
- XLT conveyor ovens, gas version H (Standard, World, Australia, Korea) with LUI/OMC controller; the electric version H Parts & Service Manual XD 9007A prints the
- Section
- Oven Troubleshooting, p. 28, LUI Service Error Codes
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related XLT pizza oven error codes
What is Comm Error?
The manual calls it an internal software error and does not describe it further.
Will the hard reset clear it?
The manual lists the hard reset as the step. If a cable or board is the cause, the error returns.
Is Comm Error the same as Software Error?
The manual gives them the same short definition, but they are separate alarms.
Need help with XLT Comm Error?
A technician confirms the cause on site and gives you the price in writing before any work starts.