Worcester Bosch Fault Code A1

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.

A1 and fault indicator LED are flashing – Controlled characteristic pump has run dry

Step	Check		Action
1.	System pressure below 1.2 bar	yes	▶ Power OFF the appliance ▶ Check appliance and system for water leaks and repair as necessary. ▶ Fill system, bleed and re-pressurise (see Installation Instructions). ▶ Turn ON appliance A1? go to step 2
		no:	go to step 2
2.	Pump seized or sticking?	yes	Free/release pump
		no:	go to step 3
3.	Audible bearing damage on pump	yes:	▶ Power OFF the appliance ▶ Disconnect the boiler electrical connection. ▶ Drain appliance. ▶ Change the pump (see Installation Instructions). ▶ Fill system, bleed and repressurise (see Installation Instructions). ▶ Reconnect the boiler electrical connection. ▶ Turn ON the appliance.
		no:	go to step 4
4.	Activate venting sequence	yes	▶ Select in the first service level, service function 2.C (Air Purge mode - see page X). ▶ Select the value 1 and store. ▶ Exit the service function. ▶ The boiler vents for eight minutes. ▶ Vent radiators manually.