BoilerFaultCodesThe 5 most common faults
Your boiler has lost the water pressure it needs to circulate heat, likely because there is a small leak somewhere in your radiator pipes or the boiler itself.
Locate the filling loop, which is a silver braided hose with a valve positioned underneath the boiler.Open the valve(s) to allow a small amount of cold water into the system until the pressure gauge needle sits back in the green zone, usually between 1.0 and 1.5 bar.Close the valve(s) tightly to stop the flow and ensure the pressure remains steady.
Your boiler is currently trying to light the flame, which is a normal part of its startup sequence.
Why it happens: This status occurs when the boiler sends an electrical spark to the burner to ignite the gas and start the heating process. If the light continues to flash without the boiler firing up, it usually means the system is struggling to sense a flame or the gas is not reaching the burner correctly. While it is often just a normal part of the startup sequence, a persistent flash suggests a component like the ignition lead or gas valve is failing.
Observe the light to see if it stops flashing and stays on (solid) or turns off once the boiler is runningCheck if the gas supply is turned on if the boiler fails to light after several attemptsPress the reset button if the light continues to flash without the boiler firing up
Your boiler has become too hot and has automatically turned itself off to prevent damage or dangerous conditions.
Full guide for Overheat thermostatThis light simply indicates that there is power reaching the boiler and it is switched on.
Why it happens: This is not actually a fault, but a confirmation that your boiler is receiving electrical power from the main supply. It indicates that the internal circuitry is live and the appliance is ready to start the ignition process once there is a demand for heating or hot water. If this light is off, it usually means there is a tripped fuse, a blown internal fuse, or the isolation switch has been turned off.
Check that the boiler power switch is onEnsure no other fault lights are flashingMonitor the boiler for normal operation
Your boiler is receiving power and is currently standing by, meaning it is ready to operate correctly.
Verify the boiler's thermostat or external heating controller is set to demand heatCheck that the radiator or hot water setting is turned onEnsure radiators are not turned down at the thermostatic valve
on the Ideal Classic Slimline FF 330 360
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 Ideal 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