Sime Format C Combi Fault codes & diagnostics

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

Combi Natural Gas 1998-2008 Discontinued

GC Numbers 47-719-1247-719-1347-719-21

Download the Sime Format C Combi 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 →

Just want the most common Sime Format C Combi faults?

The top 6 problems in plain English — with causes, DIY checks and repair costs.

Fault codes

All 3 documented codes

Tap any card for details

LED / flash-pattern codes

Digital codes