XLT Pizza Oven Error Code Under Temp: 15F Below Set Point

What does XLT Under Temp mean?

After an XLT conveyor oven first reaches its set point, the controller keeps checking that it stays near it. If the actual temperature sits 15F (9C) or more under the set point for more than thirty minutes, the controller displays Under Temp on the LUI, with the HEAT LED flashing and the Alarm LED lit. A thirty-minute delay is long, so this alarm is meant for an oven that cannot recover, not for the short dip when a load of cold dough goes in. The manual notes that changing the set point resets the timer, which gives the oven a fresh start. No causes are listed. The hard reset is the manual's action, followed by a call to XLT if the alarm persists. Anything that limits heat input or lets heat escape faster than the burner supplies it could be behind this, and the controller only reports the result.

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

• Under Temp alarm on the LUI display
• HEAT LED flashing with Alarm LED on
• Pizzas coming out pale or undercooked
• Oven temperature that stays under set point despite the burner running

Possible causes

Likely causes — what usually sits behind Under Temp on this control. A technician confirms which one it is before any part is replaced.

• Burner running but at reduced output because of low gas pressure
• Oven door openings or heavy loading pulling the temperature down for long periods
• Oven probe reading higher than the real temperature
• Burner or blower dirty enough to limit heat

Safe checks before calling for service

How a technician diagnoses Under Temp

1. Read the alarm and compare the display with an independent thermometer.
2. Check gas supply pressure at the oven while the burner is firing.
3. Inspect the burner and blower for dirt that limits heat.
4. Check the oven probe for an accurate reading.
5. Repair the cause and watch the oven hold temperature through a loaded period.

How Under Temp differs from similar codes

Under Temp watches the oven after set point is reached. Ignition Error watches the first minutes after the controller asks the burner to light.

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.