BoilerFaultCodesThe 6 most common faults
Your boiler's fan is failing to maintain a steady speed, which prevents the system from safely drawing in air and exhausting gases.
Why it happens: This fault occurs when the boiler's internal computer detects that the fan is spinning at an inconsistent or incorrect speed to safely clear exhaust gases. The most common reason is a mechanical failure within the fan motor or a communication error caused by damaged wiring or a faulty control board. Without a steady and predictable airflow, the boiler shuts down as a safety precaution to prevent improper combustion.
Full guide for 29Your boiler has detected a fault with its internal temperature sensor, meaning it cannot safely measure the heat of the water and has stopped working as a precaution.
Why it happens: This fault occurs when the boiler's control board loses its connection to the flow temperature sensor or receives an incorrect electrical signal. Most commonly, this is caused by the internal sensor failing due to age or the electrical wiring becoming damaged or loose. Because the boiler no longer knows how hot the water is, it shuts down to prevent the system from dangerously overheating.
Full guide for F01Your boiler has stopped working because one of its internal heat sensors has developed a fault and can no longer read the temperature correctly.
Why it happens: This fault occurs when the boiler's control system detects that the S2 temperature sensor has developed an electrical short circuit, meaning it can no longer safely track the heat level. The most common reason is that the sensor's internal components have failed due to age or heat stress, or moisture has compromised the electrical connections. Because the boiler doesn't know the exact temperature of the water, it shuts down as a safety precaution to prevent overheating.
Full guide for F02Your boiler has stopped working because its internal temperature sensor cannot send information to the main control board.
Why it happens: This fault occurs when the boiler's main control board loses its electrical connection with the primary temperature sensor. This is usually caused by the internal sensor failing completely or a loose connection in the wiring harness that prevents data from being transmitted. Without this temperature reading, the boiler shuts down as a safety precaution to prevent overheating.
Full guide for F03Your boiler has stopped working because it cannot detect a signal from the internal sensor that monitors the temperature of your hot water.
Why it happens: This fault occurs when the boiler's control board loses communication with the sensor responsible for monitoring your hot water temperature. The most common cause is the sensor itself failing internally, but it can also be triggered by a loose connection or damaged wiring between the sensor and the main circuit board.
Full guide for F04Your boiler has stopped working because an internal temperature sensor that monitors your hot water or heating has developed an electrical fault.
Why it happens: This fault occurs when the boiler's control board detects an incorrect electrical signal from the temperature sensor, indicating a short circuit. The most common reason is that the internal components of the sensor have failed due to age, or moisture has compromised the electrical connections. Without an accurate temperature reading, the boiler shuts down as a safety precaution to prevent overheating.
Full guide for F05on the Intergas Rapid 32
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Intergas shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue