How much does it cost to fix Grant error code Red neon lit?

Typical repair cost for the Grant Red neon lit fault is £120-250 including labour.

Red neon lit High

Grant Red neon lit Fault Code

Q: What does the Grant Red neon lit fault code mean?

Your boiler has automatically turned off because it detected that the internal water temperature became dangerously high.

Also written as REDNEONLIT — same fault.

The Grant Red neon lit fault code means: your boiler has automatically turned off because it detected that the internal water temperature became dangerously high.. It appears on 1 Grant model in our database.

Technical description: Overheat thermostat has operated

Typical repair cost £120-250 (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 Red neon lit fault code

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

Vortex Combi 70 Repair: £120-250

Source

Grant Red neon lit 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 27 April 2026