BoilerFaultCodesRavenheat 12 Fault Code
The Ravenheat 12 fault code means: your boiler's internal thermometer for the central heating system has stopped working correctly, which means the system cannot monitor or control the water temperature.. It appears on 8 Ravenheat models in our database.
Technical description: Failed heating sensor – issue with heating sensor and could need replacing
What causes the Ravenheat 12 fault?
This fault occurs when the boiler's central heating sensor either develops an electrical short or stops communicating with the main control board. The most common reason is that the internal thermistor has reached the end of its lifespan or has been damaged by constant temperature fluctuations, preventing the boiler from safely monitoring heat levels.
This fault is frequently seen in autumn when the heating system is first turned back on after being dormant all summer, putting sudden thermal stress on the aging sensor.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ravenheat models that show the 12 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ravenheat 12 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 27 April 2026