Vulcan Commercial Fryer Error Code PROBE OPEN: Probe Circuit Open
PROBE OPEN on a Vulcan PowerFry with the Computer (C) control means the temperature probe circuit is open. The control cannot tell how hot the oil is, so it will not run the burner. Switch off, let the oil cool, check that nothing presses on the probe lead and call us if it stays.
High: the fryer will not heat until the probe circuit is restored.
What does Vulcan PROBE OPEN mean?
A Computer (C) control reads oil temperature from a resistance probe in the vat. When the circuit between probe and control is open, the control has no usable reading, and running the burner blind could overheat the oil. So the display shows PROBE OPEN in place of a temperature, and the vat stops heating. A loose or dirty plug at the control, a lead that has broken or hardened from heat near the vat wall, a probe that has failed open inside the oil and a damaged input on the control board can each open the circuit. These look identical on the screen. Because the fryer will not heat until the circuit is complete, nothing the operator does in the menus changes it. Checking for pinched or hanging leads is safe once the oil is cool, and a restart shows whether the problem was a momentary contact.
Affected models and control systems
This applies to Vulcan VK/TR PowerFry gas fryers with the Computer (C) control, including the 1TR45, 1VK65 and 2TR85. The Solid State (D) control words the same condition as OPEN PROBE.
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 OPEN where the temperature should be
- Burner not firing
- Oil cooling down in the vat
- Display otherwise working normally
Possible causes
Listed in Vulcan's documentation
- A probe connector that is loose or dirty where it meets the control
- A broken or heat-hardened probe lead near the vat wall
- A resistance probe that has failed open inside the oil
- A damaged probe input on the Computer control board
Other likely causes — what usually sits behind PROBE OPEN on this control. A technician confirms which one it is before any part is replaced.
- Lead hardened and cracked after years beside the burner shield
- Grease film inside the connector breaking the contact
- Board terminal loosened by vibration during basket loading
Safe checks before calling for service
- Switch the fryer off and wait for the oil to cool.
- Check that nothing hangs on the probe lead or presses against it.
- Switch the fryer on again.
- If PROBE OPEN stays, call us and tell us when it first appeared.
- If the kitchen smells of gas, get everyone out and phone the utility, and do not touch hot oil.
How a technician diagnoses PROBE OPEN
- Read the message and let the oil cool.
- Trace the probe lead and check for cracked insulation.
- Clean and reseat the connector at the control.
- Measure the probe resistance in the oil and compare with a reference thermometer.
- Test continuity along the lead.
- If the probe tests good, check the control input before replacing anything.
- The probe is mounted in the vat, so testing it means working around hot oil and a gas burner.
- A meter and reference resistance values are needed to tell a bad probe from a bad input.
- The control board sits in a panel with live wiring.
How PROBE OPEN differs from similar codes
PROBE OPEN is the Computer (C) wording of the condition that the Solid State (D) control calls OPEN PROBE.
Technical reference
- Document
- VK/TR/VFRY Gas Fryers Installation & Operational Manual F-32971 Rev U (12-17), Alarms and Error Messages p.29-30
- Maker documentation
- Vulcan owner support
- Edition
- F-32971 Rev. U (12-17)
- Models / control
- Vulcan VK/TR PowerFry Computer (C) control
- Section
- Alarms and Error Messages, printed pp. 29-30 (plus Troubleshooting Chart p. 30)
- 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 Vulcan fryer error codes
Can I cook by watching a thermometer?
No. The burner will not run without a probe reading.
Does the word OPEN mean something is open in the oil?
It describes the electrical circuit, which has a break in it.
Could it fix itself?
Only if it was a momentary contact. A cracked lead or failed probe stays open.
Need help with Vulcan PROBE OPEN?
A technician confirms the cause on site and gives you the price in writing before any work starts.