How much does it cost to fix Johnson Starley error code b19?

Typical repair cost for the Johnson Starley b19 fault is £120-350 including labour.

b19 High

Johnson Starley b19 Fault Code

Q: What does the Johnson Starley b19 fault code mean?

Your boiler has shut down because it detected that the exhaust gases are getting too hot, which is a safety measure to prevent damage or dangerous fumes.

Also written as B19 — same fault.

The Johnson Starley b19 fault code means: your boiler has shut down because it detected that the exhaust gases are getting too hot, which is a safety measure to prevent damage or dangerous fumes.. It appears on 3 Johnson Starley models in our database.

Technical description: Burner blocked due to high flue temperature

Typical repair cost £120-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Johnson Starley models that show the b19 fault code

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

Source

Johnson Starley b19 fault code information on this page is sourced and cross-checked against the official Johnson Starley service / installation manuals for each affected model.

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