What does Vulcan Hart PROB mean?

The PROB display indicates the fryer controller has detected a fault in the temperature measuring or control circuit. This means the RTD temperature probe or the controller board itself has failed, and the unit can no longer reliably monitor frypot temperature.

What does Vulcan Hart HOT mean?

The HOT display means the frypot temperature has exceeded 410°F (210°C), which is beyond the safe operating limit. The controller immediately disables heat demand, cancels any active cooking cycle, and locks out all operator buttons.

What does Vulcan Hart COOL mean?

The COOL display means the frypot temperature is more than 21°F (12°C) above the programmed setpoint when the controller is turned on or when a cook cycle is attempted.

Commercial Kitchen

Vulcan Hart error codes, decoded.

Look up any Vulcan Hart fault code below. Each one is grounded in Vulcan Hart's own service documentation — the meaning, the symptoms, the causes, and the steps to clear it.

By Octavian Ghindea

Co-founder & CTO · Reviewed August 2026

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Vulcan Hart sits in our Commercial Kitchen coverage. Every page here is transcribed from the manufacturer's manuals, not scraped from forums.

What error codes does Vulcan Hart display?

Tap a code for the full breakdown — meaning, symptoms, causes, and fix steps.

PROB

Temperature probe failure or controller failure

HOT

Frypot temperature above 410°F

COOL

Oil too hot to begin cooking cycle

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Common questions about Vulcan Hart equipment

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