AF Low

Ravenheat AF Fault Code

The Ravenheat AF fault code means: your boiler has detected that the internal temperature is getting too low and has automatically activated its built-in heater to prevent the pipes from freezing.. It appears on 3 Ravenheat models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Frost protection device operates

Engineer required

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

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Ravenheat models that show the AF fault code

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

Source

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

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