D.4 Low
Your boiler is displaying a status reading for the warm start sensor temperature rather than an error, which is part of the system's normal operational monitoring.
Technical description: Current temperature for warm stat sensor
Typical repair cost: £0 (including labour)
DIY fix possible
Press the 'back' or 'menu' button to return to the main pressure or temperature displayMonitor the boiler for any actual fault codes starting with 'F'Ensure the warm start function (if desired) is enabled or disabled via the control knob
Protect yourself from future repair bills
A boiler cover plan would cover faults like D.4 — no call-out fees, no surprises.
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