NO DHW BUT CH ON Medium

Johnson Starley NO DHW BUT CH ON Fault Code

Also written as NODHWBUTCHON — same fault.

The Johnson Starley NO DHW BUT CH ON fault code means: your boiler is successfully heating your radiators, but it is failing to send heat to your hot water tank.. It appears on 1 Johnson Starley model in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: No domestic hot water but central heating on
Typical repair cost £140-£280 (including labour)

DIY fix possible

Check if the hot water is turned on at your external programmer or timerEnsure the cylinder thermostat (usually strapped to the water tank) is turned up to at least 60°CLocate the motorised valve near your tank and check if the manual lever is stuck

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Johnson Starley models that show the NO DHW BUT CH ON fault code

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

Source

Johnson Starley NO DHW BUT CH ON 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