BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Locate the filling loop (a silver flexi-hose connected to two valves under the boiler).Open the valves slowly to allow mains water to enter the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (between 1.0 and 1.5 bar).Close both valves tightly to prevent over-pressurisation.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Locate the external filling loop, usually a small silver braided hose with one or two valves underneath the boiler.Open the valve(s) slowly to allow mains water into the system while watching the pressure gauge on the front panel.Stop filling once the needle reaches the green zone, typically between 1.0 and 1.5 bar, and ensure the valves are tightly closed.
Your boiler has stopped working because it has either lost water pressure or a safety sensor has detected that it is getting too hot.
Check your pressure gauge located on the boiler; if it is below 1 bar, increase it using the external filling loop until it reaches 1.5 barSwitch the boiler off at the fused spur for 30 seconds and switch it back on to reset the systemEnsure all radiator valves are fully open to allow water to circulate freely
Your boiler has stopped working because it is unable to accurately measure the temperature of the water flowing through the system.
Full guide for F.00Your boiler has stopped working because it is unable to accurately measure the temperature of the water returning to the system, causing the unit to shut down as a precaution.
Full guide for F.01Your boiler has stopped working because a sensor that measures the temperature of the water leaving the boiler is sending a faulty signal to the internal computer.
Full guide for F.10on the Glow-worm Ultimate 3 25R
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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