Fault Codes

Shown below are Worcester Bosch Fault Codes. Please note some faults may be applicable only to certain models or types of boiler.


Display CodeDescriptionRemedyResources
A1Pump has run dry or pump has stalled/seized.Check for water leaks.
Free the pump or replace.
A7Hot water NTC sensor defective.Check hot water NTC sensor and connecting lead for circuit breaks/short circuits.
A8Break in communication to TD200 or/and RT10.Check electrical connections.
b1Code plug not detected.Insert code plug correctly, test and replace if necessary.
C6Fan speed too low.Check fan lead and connector, and fan; replace as necessary.
E2CH flow NTC sensor defective.
Check CH flow NTC sensor and connecting lead.
E9Safety temp. limiter in CH flow has tripped.Check system pressure, check safety temp. limiters, check pump operation, check fuse on pcb, bleed appli- ance.
EAFlame not detected.Is gas cock turned on? Check gas supply pressure, power supply, igniter electrode and lead, ionisation sensing electrode and lead, flue duct and C02 level.
F0Internal error.Check electrical connector contacts, programmer inter- face module ignition leads are not loose; replace pcb if necessary.
F7Flame detected even though appliance switched off.Check electrode assembly, dry pcb. Flue clear?
FAFlame detected after gas shut off.Check gas valve and wiring to gas valve. Clean conden- sation trap and check electrode assembly. Flue clear?
FdReset button pressed by mistake.Press reset button again.
-¦¦- and XXSiphon fill modeWait approx 15 mins



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