How much does it cost to fix Johnson Starley error code 41?

Typical repair cost for the Johnson Starley 41 fault is £120-£280 including labour.

41 High

Johnson Starley 41 Fault Code

Q: What does the Johnson Starley 41 fault code mean?

Your boiler has lost its connection with the water pressure sensor, which means it cannot confirm if there is enough water inside to run safely.

The Johnson Starley 41 fault code means: your boiler has lost its connection with the water pressure sensor, which means it cannot confirm if there is enough water inside to run safely.. It appears on 6 Johnson Starley models in our database.

Technical description: No water pressure signal recievced fom MMI

Typical repair cost £120-£280 (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 41 fault code

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

Source

Johnson Starley 41 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