How much does it cost to fix Johnson Starley error code 37?

Typical repair cost for the Johnson Starley 37 fault is £0-160 including labour.

37 High

Johnson Starley 37 Fault Code

Q: What does the Johnson Starley 37 fault code mean?

Your boiler has detected that the water pressure in the central heating system is too low and it has stopped working as a safety precaution.

The Johnson Starley 37 fault code means: your boiler has detected that the water pressure in the central heating system is too low and it has stopped working as a safety precaution.. It appears on 6 Johnson Starley models in our database.

Technical description: Low system water pressure

Typical repair cost £0-160 (including labour)

DIY fix possible

Locate the external filling loop, which is usually a silver braided flexible hose under or near the boiler.Slowly open the one or two valves on the hose to let water into the system.Watch the pressure gauge and close the valves tightly once the needle reaches between 1.0 and 1.5 bar.

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Johnson Starley models that show the 37 fault code

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

Source

Johnson Starley 37 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