BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the filling loop (a metal braided hose or built-in tap underneath your boiler).Slowly open the tap or valve to let mains water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically 1 to 1.5 bar).Close the valve tightly to stop the flow.
Your boiler has detected that the water pressure inside the heating system is too low to operate safely.
Locate the external filling loop—a flexible silver hose connecting the two pipes under your boiler.Open the valves on both ends of the loop to allow mains water into the system.Monitor the pressure gauge on the boiler front until it reaches 1.5 bar, then securely close both valves.
Your boiler has lost the signal from the sensor that monitors the water temperature, meaning it cannot safely heat your home.
Full guide for F.00Your boiler has detected that water is not circulating properly through the system, which prevents it from heating your home or water safely.
Full guide for F.75Your boiler has lost the signal from the sensor that monitors the temperature of the water coming back into the heating system, so it has shut down as a precaution.
Full guide for F.01Your boiler has lost the ability to accurately measure the temperature of the water flowing through the system, so it has shut down as a precaution to prevent overheating.
Full guide for F.10on the Glow-worm MicraCom
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
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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