How much does it cost to fix Johnson Starley error code ER 15 + RESET?

Typical repair cost for the Johnson Starley ER 15 + RESET fault is £120-300 including labour.

ER 15 + RESET High

Johnson Starley ER 15 + RESET Fault Code

Q: What does the Johnson Starley ER 15 + RESET fault code mean?

Your boiler has detected that the water is getting too hot too quickly because it isn't moving through the system properly.

Also written as ER15RESET — same fault.

The Johnson Starley ER 15 + RESET fault code means: your boiler has detected that the water is getting too hot too quickly because it isn't moving through the system properly.. It appears on 1 Johnson Starley model in our database.

Technical description: Differential over-temp across CH flow/return

Typical repair cost £120-300 (including labour)

DIY fix possible

Check that all radiator valves are fully openEnsure the central heating bypass valve is not closedCheck if the pump is making a humming sound, suggesting it might be stuckPress and hold the RESET button to see if the code clears

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Johnson Starley models that show the ER 15 + RESET fault code

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

Warmcair DW Repair: £120-300

Source

Johnson Starley ER 15 + RESET 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