Worcester Bosch Fault Code C6

Welcome to the fault-codes section of this site. The following table or page contains the information required to help repair and diagnose the fault codes being shown on the boiler display. You may be guided through the fault finding sequence or steps, for rectifying your boiler with this fault code. Suggested repair solutions may be provided by a link to a repair page. NB Some fault codes are only applicable to a specific range of boilers only.

C6 and fault indicator LED are flashing. Fan speed too low

Step	Check		Action
1.	Fan cable connector correctly connected on fan?	yes:	go to step 2
		no:	▶ Switch OFF the appliance. ▶ Reconnect connector. ▶ Switch ON the appliance. C6? go to step 2
2.	Check power supply to appliance, check supply with all electrical appliances on. Is the supply voltage within tolerance (230 V AC 10)?	yes:	go to step 3
		no:	▶ Switch off some electrical appliances. go to step 3
3.	Is fan cable defective? ▶ Switch OFF the appliance. ▶ Disconnect the boiler power connection. ▶ Measure the fan lead for continuity. Is there continuity for each one of the cores?	yes:	go to step 4
		no:	▶ Replace fan cable. ▶ Reconnect the appliance power connection. ▶ Switch ON the appliance. C6? go to step 4
4.	Fan defective.	yes:	▶ Switch OFF the appliance. ▶ Disconnect the boiler power connection. ▶ Un-plug the connection wire. ▶ Replace fan. ▶ Push on the connection wire. ▶ Reconnect the appliance power connection. ▶ Switch ON the appliance. C6? go to step 5
5.	The PCB is damaged.		▶ Make a note of the altered service function settings (see table 4 on page 6) in order to keep the altered values. ▶ Switch OFF the appliance. ▶ Disconnect the boiler power connection. ▶ Change PCB control board. ▶ Reconnect the appliance power connection. ▶ Switch ON the appliance. ▶ Restore service settings previously noted down.