BoilerFaultCodes
The most common Grant faults
Your boiler has lost electrical power and cannot start any heating or hot water functions.
Why it happens: This fault occurs when the boiler is not receiving the electrical current required to operate its internal components. The most common reason is a simple blown 3-amp fuse in the fused spur switch or a tripped circuit breaker in your home's main consumer unit. In more serious cases, it can be caused by a surge that has damaged the boiler's main control board.
Check that the boiler's main power switch is turned to the 'ON' position.Inspect your home's main consumer unit (fuse box) to see if a circuit breaker has tripped.Check the fused spur switch (usually near the boiler) and replace the 3-amp fuse if it has blown.
Your boiler is not detecting that a hot tap has been turned on, which is preventing it from heating your water.
Why it happens: This fault occurs when the boiler fails to detect water moving through the pipes when you turn on a hot tap. The most common reason is that the internal sensor used to trigger the burner has become stuck or damaged, preventing the boiler from knowing there is a demand for hot water. In some cases, a perished rubber diaphragm or a blockage within the unit is stopping the mechanical parts from moving correctly.
Full guide for Vortex Pro Combi FlowYour boiler has stopped working to protect itself and needs to be restarted, though it may take a few attempts to get it running again.
Check your external oil supply tank to ensure you have enough fuel and that any isolation valves are open.Locate the reset button on the boiler casing (or the burner unit) and press it once firmly.Wait for the boiler to attempt an ignition cycle; if it fails again, do not force the reset more than three times.
Your boiler has stopped working because the burner failed to light or stay lit during its startup sequence.
Check that you have fuel in your oil tankEnsure the oil supply valve is fully openPress the illuminated red reset button once to see if the burner restarts
Your boiler has tried to start several times but keep losing its flame, so it has locked itself for safety reasons.
Check that you have enough heating oil in your storage tankEnsure the oil supply valves are fully openPress the burner reset button once (if the fault persists, call a professional)
Your boiler has switched itself off because it has become too hot internally, likely due to a blockage or a pump issue stopping the water from moving.
Check that all radiator valves are fully open and there is no air trapped in the systemEnsure the system pressure is between 1 and 1.5 bar on the pressure gaugeOnce the boiler has cooled down, locate and press the manual reset button on the overheat thermostat behind the front casing
Your boiler has become too hot and has automatically shut itself down to prevent damage or safety issues.
Identify the black reset button cover on the control panelUnscrew the cover and firmly press the small reset button underneath until it clicksEnsure your radiator valves are open and the system pressure is correct
Your boiler has become too hot and has automatically shut itself down to prevent damage or safety issues.
Allow the boiler to cool down for at least 20 minutes.Locate the overheat reset button under the black screw cap on the control panel.Unscrew the cap and firmly press the small reset button until it clicks.Check that your radiator valves are open and the system pressure is correct.
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