How much does it cost to fix Grant error code Red steady on?

Typical repair cost for the Grant Red steady on fault is £120-280 including labour.

Red steady on High

Grant Red steady on Fault Code

Q: What does the Grant Red steady on fault code mean?

Your boiler has stopped working because it cannot detect a flame or is struggling to ignite the fuel properly.

Also written as REDSTEADYON — same fault.

The Grant Red steady on fault code means: your boiler has stopped working because it cannot detect a flame or is struggling to ignite the fuel properly.. It appears on 6 Grant models in our database.

Technical description: UV sensor defective or dirty oil valve defective fault – ignition transformer badly regulated burner, oil fuel not present

What causes the Grant Red steady on fault?

This fault happens when the boiler's internal computer can no longer detect a flame, causing it to shut down for safety. The root cause is typically a dirty light sensor that cannot 'see' the fire, or a mechanical failure in the parts that deliver the oil and spark needed to create the flame.

This issue is more frequent during the first cold snap of autumn when settled debris in the fuel tank or a worn nozzle can prevent the burner from firing up after being idle all summer.

Typical repair cost £120-280 (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 steady on fault code

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

Source

Grant Red steady on 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