Your boiler has detected an issue with the airflow system, which means it cannot safely vent exhaust gases, so it has shut down to prevent any risk.

Technical description

Pressureswitch Check:Cableharness,vacuumhose(blockage),supplyair/fluegas route(blockage),panel(correcttype),fluepipe(length),airpressure sensor,settings(ifnecessary,switchD.132tomultiple-flueconfigura- tion),pressureswitch,fan.