Worcester Bosch · Greenstar Si Compact ErP
D3 232External cut-off switch activated
This code applies to Greenstar 25Si Compact ErP, Greenstar 30Si Compact ErP. Fault codes narrow down the likely problem, but they do not replace a model-specific diagnosis.
What you can safely check
- Do not remove the boiler case.
- Record the full code and model, then arrange a Gas Safe registered engineer.
How an engineer may fix it
Follow the model-specific fault-finding procedure, test the indicated circuit or component, repair the cause and recommission the appliance.
Manufacturer source: Worcester Bosch — Greenstar Si Compact ErP Installation, Commissioning and Servicing Instructions (6 720 813 278). Checked 15 August 2026. The appliance manual and an engineer’s on-site diagnosis take precedence. Never remove the boiler case yourself.