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 working fine for your radiators, but a specific internal component is failing to switch over to provide hot water to your taps.. 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 operates correctly
Typical repair cost £150-250 (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 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 7 July 2026