Daikin D2CND Fault codes & diagnostics

1 fault code with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

Combi Natural GasLPG 24-35 kW 2017-present
GC Numbers 47-439-0147-439-0247-439-03
Download the Daikin D2CND manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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All 1 documented codes

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HJ-09

Your boiler has detected that the water pressure is too low to operate safely, causing it to shut down temporarily.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.
  2. Slowly open the one or two taps/levers on the filling loop until you hear water moving.
  3. Watch the pressure gauge and close the taps firmly once the needle reaches 1.5 bar.

Parts commonly replaced

  • Filling loop valve
  • Pressure sensor
  • Expansion vessel

Related codes

1 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

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