BoilerFaultCodesThe 6 most common faults
Your boiler is currently on standby because your thermostat, timer, or smart heating controls are not telling it to turn on.
Check that your room thermostat or smart controller is switched on and set to a higher temperature than the current room temperature.Replace the batteries in your wireless room thermostat or timer.Check that any external programmer or time clock is set to the correct 'on' schedule.
Your boiler has temporarily shut down because the internal water pressure has dropped too low to run safely.
Locate the filling loop underneath your boiler.Open the valves gently to let water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valves tightly and press the reset button on your boiler.
Your boiler has temporarily stopped working because the water pressure inside the system has dropped too low.
Locate the filling loop underneath your boiler, which usually consists of a flexible silver hose with one or two small valves.Slowly open the valves to let mains water into the heating system, keeping an eye on the pressure gauge.Stop filling once the needle on the pressure gauge reaches the green zone (ideally between 1.0 and 1.5 bar) and firmly close both valves.
Your boiler has temporarily lost its electrical power supply or experienced a fluctuation in the mains voltage.
Check that the fused spur switch next to the boiler is turned on.Check your household consumer unit (fuse box) to see if a trip switch has activated.Try resetting the boiler using its reset button once power is verified.
Your boiler has stopped working because the water pressure inside the system has dropped too low.
Locate the filling loop beneath your boiler.Open the valves gently to let water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves firmly and check the pressure.
Your boiler has automatically shut down because the internal water pressure has dropped too low to operate safely.
Locate the filling loop (usually two valves connected by a silver braided flexible hose underneath the boiler).Open both valves slowly to let mains water into the heating system.Watch the pressure gauge on the front panel until the needle reaches between 1.0 and 1.5 bar, then firmly close both valves.
on the Vaillant ecoMAX 824E
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 Vaillant 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