Common problems guide

The most common Worcester Bosch Greenstar 30 CDi Conventional problems

The faults most likely to send a Worcester Bosch Greenstar 30 CDi Conventional into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.
3 documented codes
3 most common
0 DIY-safe checks
3 engineer needed

The 3 most common faults

01
F7 Engineer

Flame detected even though appliance switched off. Check electrode assembly, dry pcb. Flue clear?

Full guide for F7
02
FA Engineer

Flame detected after gas shut off. Check gas valve and wiring to gas valve. Clean condensation trap and check electrode assembly. Flue clear?

Full guide for FA

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Worcester Bosch shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
See the full 3-code list for the Worcester Bosch Greenstar 30 CDi Conventional

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →