BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the amount of water inside your heating system has dropped below the minimum level required to operate safely.
Locate the external filling loop, usually a silver braided hose with one or two valves underneath your boiler.Slowly open the valves until you hear water flowing and the pressure gauge on the front of the boiler rises into the green zone (typically between 1.0 and 1.5 bar).Close the valves tightly to stop the flow and ensure the pressure gauge stays steady.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Locate the filling loop (a flexible silver hose connecting two pipes near the bottom of the boiler).Open the valves at both ends of the hose to allow water into the system while watching the boiler's pressure gauge.Close both valves firmly once the needle on the gauge reaches the green zone, typically between 1.0 and 1.5 bar.
Your boiler has lost the signal from the sensor that monitors the water temperature, causing it to shut down for safety reasons.
Full guide for F.00Your boiler has lost its connection to the sensor that monitors the temperature of the water returning to it, so it has safely shut down to prevent overheating.
Full guide for F.01Your boiler has stopped working because it is unable to accurately measure the temperature of the water inside it due to a faulty electrical sensor connection.
Full guide for F.10Your boiler has stopped working because it is unable to accurately measure the temperature of the water returning to it, preventing it from heating safely.
Full guide for F.11on the Glow-worm Flexicom 24c / 28c
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 Glow-worm 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