Worcester Bosch Greenstar Fault codes & diagnostics

6 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

Regular Gas 2004-present
GC Numbers 41-311-6341-311-6541-311-6641-311-7841-406-0347-406-6441-406-03
Download the Worcester Bosch Greenstar manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
6 Unrated
Versions & GC numbers

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
41-311-63 Greenstar 12 Ri 2004–2015
41-311-65 Greenstar 24 Ri 2004–2015
41-311-66 Greenstar 24 Ri 2004–2015
41-311-78 Greenstar 18Ri 2005–2015
41-406-03 Greenstar FS 30 CDi Regular 2008–2015
47-406-64 Greenstar 30 2014–2015
41-406-03 Greenstar FS 30CDi Regular ErP 2008–present

Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.

Just want the most common Worcester Bosch Greenstar faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 6 documented codes

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LED / flash-pattern codes
Digital codes
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