BoilerFaultCodesIdeal F12 Fault Code
The Ideal F12 fault code means: your boiler's internal pump has stopped spinning, which means hot water cannot be moved around the system to heat your home or taps.. It appears on 3 Ideal models in our database.
Technical description: Pump Rotor Blocked: Clear blockage
What causes the Ideal F12 fault?
This fault occurs when debris, such as iron oxide sludge or grit, becomes trapped inside the pump and prevents the internal motor from spinning. It can also be caused by the pump's internal components seizing up after long periods of inactivity or due to electrical failure within the pump itself.
This fault is frequently seen at the start of autumn when homeowners turn their heating back on after the pump has sat stationary throughout the summer months.
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 →Ideal models that show the F12 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal F12 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026