How much does it cost to fix Worcester Bosch error code 4-b2?

Typical repair cost for the Worcester Bosch 4-b2 fault is £0-60 including labour.

4-b2 Low

Worcester Bosch 4-b2 Fault Code

Q: What does the Worcester Bosch 4-b2 fault code mean?

Your boiler has automatically switched off the heating because it thinks the weather outside is warm enough that you don't need it.

Also written as 4B2 — same fault.

The Worcester Bosch 4-b2 fault code means: your boiler has automatically switched off the heating because it thinks the weather outside is warm enough that you don't need it.. It appears on 1 Worcester Bosch model in our database.

Technical description: Outside temperature limit for automatic changeover between summer and winter mode: 0...16...30 °C.

Typical repair cost £0-60 (including labour)

DIY fix possible

Locate the heating temperature dial or settings menu on your boiler control panel.Adjust the 'Summer/Winter' threshold setting if you want the heating to come on at higher outdoor temperatures.Check your external weather compensation sensor for any obstructions or dirt if the reading seems incorrect.

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Worcester Bosch models that show the 4-b2 fault code

Click a model for the full fault code list and model-specific repair notes.

Greenstar 2000 Repair: £0-60

Source

Worcester Bosch 4-b2 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026