Ultrafryer Commercial Fryer PROBE Error: Temperature Probe Circuit
PROBE on an Ultrafryer with the UltraStat 23 means the control cannot read a proper signal from the temperature probe. Switch the fryer off, let the oil cool, and check that the probe plug is seated at the control. If PROBE returns, the probe or its cable needs testing.
Medium: the fryer stops heating until the probe signal is restored, but there is no direct safety hazard.
- Code
- PROBE
- Maker
- Ultrafryer
- Equipment
- Fryers
- Applies to
- UltraStat 23 controller (30A216 July 2009)
What does Ultrafryer error code PROBE mean?
The UltraStat 23 reads oil temperature through a probe in the vat and watches that circuit for two kinds of trouble. If the circuit is open, the control sees no signal at all. If it is shorted, the signal is out of range, and a shorted probe also sounds an audible alarm. Either way the display shows PROBE. The owner's manual points to a defective probe or one that is not plugged in. Without a trustworthy reading the control cannot hold the oil at its set temperature, so it stops heating rather than guess. The cause can also sit in the cable between vat and control, where heat or a pinch can break a wire, or in the probe input on the board. With heat off, the oil slowly cools and cooking stops.
Affected models and control systems
This applies to Ultrafryer fryers with the UltraStat 23 controller, including the P30-14-UCP and the UG14, per manual 30A216 (July 2009).
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
- PROBE on the display
- Fryer not heating while the oil slowly cools
- Audible alarm with PROBE when the circuit is shorted
Possible causes
Listed in Ultrafryer's documentation
- A probe plug that has worked loose from its socket
- A defective temperature probe in the Ultrafryer vat
- A pinched or burned probe cable run to the UltraStat 23
- A damaged probe input on the UltraStat 23 board
Other likely causes — what usually sits behind error code PROBE on this control. A technician confirms which one it is before any part is replaced.
- Grease or moisture inside the probe connector, which changes the signal
- A cable moved during cleaning that now rubs on a hot surface
- A probe bent or knocked during a vat clean and shorted at its tip
Safe checks before calling for service
- Switch the fryer off and let the oil cool.
- Look at the probe plug at the control and make sure it is plugged in.
- Switch the fryer back on.
- The manual lists these steps. Do not reach into hot oil or drain it, and do not open panels.
- If PROBE returns, note whether an alarm sounded and call us.
How a technician diagnoses error code PROBE
- Ask whether PROBE appeared suddenly or after cleaning, and whether the alarm sounded.
- With the fryer cool and off, inspect the plug, cable run and probe tip for damage.
- Measure probe resistance at the plug and compare it with the expected value.
- Flex the cable while watching the meter to find an intermittent open or short.
- If probe and cable pass, test the probe input on the controller.
- Replace what failed, heat the oil, and confirm PROBE stays away.
- The probe sits in hot oil and its connectors sit near the heat, so work starts with a fully cooled fryer.
- Telling a failed probe from a failed controller input takes a meter and the expected resistance values.
- Test-running the fryer needs gas and hot oil, a hazard for anyone untrained.
Technical reference
- Document
- UltraStat 23 Manual 30A216, display descriptions and Troubleshooting
- Edition
- 30A216 July 2009 (footer; 229-51339 Rev A, 2007 FAST)
- Models / control
- UltraStat 23 controller (30A216 July 2009)
- 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.
Related Ultrafryer fryer error codes
Can I fry without the probe?
No. With no probe signal the control cannot hold temperature, so it stops heating.
Why did PROBE sound an alarm?
A shorted probe circuit also sounds an alarm. An open one, such as an unplugged probe, shows PROBE without it.
Is PROBE the same as the over-temperature alarm?
No. PROBE is about the signal. The over-temperature alarm means the oil really got too hot.
Need help with Ultrafryer error code PROBE?
A technician confirms the cause on site and gives you the price in writing before any work starts.