Technical description
The boiler is waiting – there was a heat demand from the on off or modulating control
What causes this fault?
This status appears when your external thermostat or heating controls have sent a signal to the boiler telling it to turn on. The boiler is physically preparing to ignite and is simply waiting for its internal startup sequence to complete. It is a normal part of the boiler's operation and does not indicate that anything is broken.
DIY fix possible
Check that your room thermostat is set to the desired temperatureEnsure your heating programmer or timer is set to an 'On' periodWait a few minutes to see if the boiler fires up automatically as part of its normal cycle