BoilerFaultCodesThe 6 most common faults
Your boiler has stopped itself from running as a safety precaution because the fuel failed to ignite properly.
Check your external oil tank has enough fuel and the isolation valve is fully openLocate the red reset button on the burner casing or control boxPress and hold the reset button for 3 seconds then release to attempt a restart
Your boiler is failing to ignite because it is not receiving any oil to burn.
Check your external oil tank gauge to ensure there is sufficient fuel remaining.Verify that the isolation valve located on the oil supply line near the boiler is set to the open position.Check if the fire valve (often a lever or button located outside the boiler casing) has been accidentally tripped and requires resetting.
Your boiler is currently switched off or not receiving any power, preventing it from heating your water or home.
Check that the fused spur switch near the boiler is turned on.Inspect your home's fuse box or consumer unit to see if a trip switch has flipped.Verify that your room thermostat and programmer are asking for heat.
Your boiler has detected a temporary issue with the burner and has safely shut itself down to prevent any damage.
Check your oil tank to ensure you have enough fuel and that the supply valve is openWait 60 seconds for the internal control unit to resetGently press the illuminated red reset button located on the burner once
Your boiler has stopped working because the amount of water in your heating system is too low to run safely.
Locate the external filling loop, which is a flexible silver hose connecting your cold water mains to your heating pipes.Open the valves at both ends of the filling loop slowly to let water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves tightly to prevent over-pressurizing the system.
Your boiler has stopped working to protect itself and needs a manual reset to try and start up again.
Locate the red reset button on the burner control boxPress and hold the button for 3 seconds, then releaseWait to hear if the burner ignites; if it locks out again, do not force further resets
on the Grant Vortex Pro 15-26
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 Grant 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