BoilerFaultCodesThe 6 most common faults
Your boiler has detected that the water temperature in your secondary heating circuit is higher than it should be, causing the system to shut down to prevent damage.
Why it happens: This fault occurs when the water temperature in your second heating zone exceeds safe limits, prompting the boiler to shut down to prevent damage. It is usually caused by a physical blockage in that specific part of the system, a failed zone valve that won't open, or a pump that isn't circulating the hot water away from the boiler quickly enough.
Full guide for 7 22Your boiler has disabled your heating system because it cannot detect or communicate with the controls that request heat for your radiators.
Why it happens: This fault occurs when the boiler’s main computer loses touch with your heating controls or receives conflicting information about how many heating zones it should be managing. It is essentially a 'handshake' failure where the boiler disables the heating to prevent damage because it no longer knows which part of the house is calling for heat. The most common reasons are a loose connection in the wiring, a failed external thermostat, or a software glitch on the main circuit board.
Full guide for 7 50Your boiler has detected that water is not flowing through the system correctly, which is preventing it from heating your home properly.
Check that all radiator valves throughout your home are fully open.Inspect the boiler pressure gauge and top it up to 1.5 bar using the filling loop if it is below 1.Reset the boiler using the reset button on the control panel.
Your boiler is struggling to push water around your heating system because the flow is blocked or restricted.
Check that all radiator valves throughout your house are fully openEnsure your system pressure is at the recommended level of 1.5 barBleed your radiators to remove any trapped air that might be blocking water flow
Your boiler is struggling to move water around your heating system effectively, usually because there is trapped air, a blockage, or low water pressure.
Check your boiler pressure gauge and top it up to 1.5 bar using the filling loop if it is below 1 barBleed all radiators in the house to release trapped airEnsure all radiator valves are fully open
Your boiler has detected that the water pressure in your heating system is too low to operate safely, so it has shut down to protect itself.
Locate the filling loop, which is usually a flexible metal hose with one or two small valves connecting your cold mains pipe to your heating pipework.Open the valve(s) slowly to allow water into the system while watching the pressure gauge on the front of the boiler.Stop filling as soon as the needle reaches the green zone, typically between 1.0 and 1.5 bar, then tightly close the valve(s).
on the Ariston E-Combi One
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 Ariston 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