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Worcester Bosch — Greenstar 25Si / 30Si
Select a fault code
Fault Codes
C6Fan speed fault🔧 Engineer Required
Fan not operating within required speed range.
CE0Gas valve relay fault🔧 Engineer Required
Gas valve relay fault on PCB.
D5Condensate blockage🔄 Try Reset
Condensate drain is blocked or frozen — common in cold weather.
E1Low water pressure🔄 Try Reset
System pressure dropped below minimum level.
E2NTC sensor fault🔧 Engineer Required
Flow temperature sensor fault — reading outside normal range.
E5Overheating lockout🔧 Engineer Required
Boiler temperature exceeded safe limits, high limit thermostat tripped.
EAIgnition lockout🔄 Try Reset
Boiler attempted to ignite but failed to establish a flame.
F7Ghost flame🔧 Engineer Required
Flame detected with no ignition demand.
📞 Worcester Bosch Direct Support
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Download ↗Worcester BoschManuals & Documentation
Installation guides, user manuals, technical documentation
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