BoilerFaultCodesThe 6 most common faults
Your boiler has sensed that the water returning from your radiators is hotter than the water leaving the boiler, which usually means there is a circulation problem or a sensor fault.
Why it happens: This fault occurs when the boiler's internal sensors detect that the system is operating in reverse, with the return pipe being hotter than the flow pipe. The most common reason is a circulation failure, often caused by a faulty pump or a blockage in the heat exchanger that prevents water from moving through the boiler correctly. It can also be triggered if one of the temperature sensors has failed and is providing an incorrect reading to the control board.
Full guide for 24Your boiler has detected an internal fault with the component that controls the gas supply, meaning it has shut down to keep your home safe.
Why it happens: This fault occurs when the boiler's control system loses communication with the fan or detects that it isn't spinning at the required speed. The most common reasons are a mechanical failure of the fan motor itself, loose internal wiring, or a fault on the main circuit board failing to send power to the unit.
Full guide for 29Your boiler has detected an internal electrical fault with the component that controls the gas supply, meaning it has safely shut itself down to prevent operation.
Why it happens: This fault occurs when the boiler detects that the water coming back from your radiators is much hotter than the water it just sent out, which shouldn't happen during normal operation. The most common reason is a lack of water flow caused by a blockage, trapped air, or a failing pump, but it can also be triggered if the electronic sensors that measure temperature become faulty and provide 'garbage' readings to the control board.
Full guide for 30Your boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Why it happens: This fault occurs when the boiler's main flow sensor, which monitors the temperature of the water leaving the heat exchanger, fails to provide a consistent or logical reading. The most common reason is that the internal electrical component of the sensor has worn out or developed a short circuit, preventing the control board from knowing if the water is at a safe temperature.
Full guide for 10Your boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Why it happens: This fault occurs when the boiler's main flow sensor, which monitors the temperature of the water leaving the heat exchanger, fails to provide a consistent or logical reading. The most common reason is that the internal electrical component of the sensor has worn out or developed a short circuit, preventing the control board from knowing if the water is at a safe temperature.
Full guide for 12Your boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Why it happens: This fault occurs when the boiler's main flow sensor, which monitors the temperature of the water leaving the heat exchanger, fails to provide a consistent or logical reading. The most common reason is that the internal electrical component of the sensor has worn out or developed a short circuit, preventing the control board from knowing if the water is at a safe temperature.
Full guide for 13on the Intergas Combi Compact HRE 36/30
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