D.73 Low
Your boiler is notifying you that it has adjusted the temperature settings for its pre-heat function to ensure hot water is ready when needed.
Technical description: Off set for warm start target value
Typical repair cost: £0-120 (including labour)
DIY fix possible
No action is typically required as this is often an advisory status code rather than a hard fault.If hot water temperatures feel inconsistent, check your boiler's hot water temperature dial/setting.Perform a simple reset by pressing the 'flame' or 'reset' button to see if the status clears.
Protect yourself from future repair bills
A boiler cover plan would cover faults like D.73 — no call-out fees, no surprises.
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Parts commonly replaced
- None (usually software logic)
- NTC Thermistor (if persistent)
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