Ultrafryer Commercial Fryer Over-Temperature Alarm: Vat Too Hot

What does Ultrafryer Over-temperature alarm mean?

The UltraStat 23 compares the vat temperature with the highest set point programmed for that vat. If the oil climbs more than 40 degrees above it, the control sounds a continuous alarm. This is a protective alarm for a burn and fire risk, because oil that hot is close to its flash point. It means something is not holding the temperature. The probe may read low and call for too much heat, the gas valve or heat relay may be stuck open, the high limit may not be cutting the heat, or the controller output that calls for heat may be stuck on. The alarm keeps sounding until the temperature comes down, so silence alone does not mean the cause is gone. Do not drain, filter, carry or stir hot oil.

Affected models and control systems

This applies to the Ultrafryer P30-14-UCP with the UltraStat 23 controller, as described on page 17 of the UltraStat 23 manual.

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

• Continuous audible alarm
• Oil smoking or visibly hotter than the set temperature
• Display reading well above the programmed setting

Possible causes

Listed in Ultrafryer's documentation

• The temperature probe and how accurately it reads
• The gas valve or heat relay staying open
• The high limit and its wiring
• The controller output that calls for heat

Other likely causes — what usually sits behind Over-temperature alarm on this control. A technician confirms which one it is before any part is replaced.

• A probe that drifted or was bumped, so it reads cooler than the oil
• A relay with burned contacts that sticks closed after the call for heat ends
• An ignition problem that leaves the burner running longer than it should

Safe checks before calling for service

How a technician diagnoses Over-temperature alarm

1. Let the oil cool, then check the fill level and look for burnt, dark oil.
2. Compare the probe reading with a calibrated thermometer.
3. With gas isolated, test the gas valve and heat relay for sticking.
4. Check the high limit and its wiring for continuity and opening temperature.
5. Test whether the controller output stays on without a request for heat.
6. Replace the failed part, then heat to set point and confirm the alarm stays quiet.

Technical reference

Document

UltraStat 23 Manual p.17

Edition

30A216 July 2009 (footer; 229-51339 Rev A, 2007 FAST)

Models / control

UltraStat 23 controller

Section

Display Descriptions, printed p. 9 (images with descriptions); FILTER prompt on p. 7; no fault code table

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.