D.3 Low
Your boiler is currently showing you the live temperature of the hot water it is producing, which is a normal status message rather than an error.
Technical description: Hot water flow temperature reading
Typical repair cost: £0 (including labour)
DIY fix possible
No action is required as this is a status code, not a fault.If the boiler is stuck on this code and not providing heat, try resetting the boiler.Ensure your hot water taps are fully closed.
Protect yourself from future repair bills
A boiler cover plan would cover faults like D.3 — no call-out fees, no surprises.
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