PROBE FAULT High

Grant PROBE FAULT Fault Code

Also written as PROBEFAULT — same fault.

The Grant PROBE FAULT fault code means: your boiler has lost the signal from one of its internal temperature sensors, which is preventing it from heating your home safely.. It appears on 1 Grant model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Probe fault is scrolling across the bottom of the burner control panel display. This may be due to plugs not being correctly fitted to the burner.
Typical repair cost £150-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Grant models that show the PROBE FAULT fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Grant PROBE FAULT fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026