Daikin D2TND024 Fault codes & diagnostics

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

System Natural Gas 24 kW 2017 onwards
GC Number 41-464-01
Download the Daikin D2TND024 manualThe official installation and service manual (PDF), the document these fault codes were read from. PDF

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Versions & GC numbers

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
41-464-01 D2TND024A4AA 2017–present

Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.

Fault codes

All 1 documented codes

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Err HJ-09

Your boiler has temporarily stopped working because the water pressure inside the system has dropped too low.

High DIY-safe

What to check first

  1. Locate the filling loop underneath your boiler or check your user manual for system-specific repressurising instructions.
  2. Open the valves slowly to allow water into the system while watching the pressure gauge.
  3. Stop filling when the needle reaches between 1.0 and 1.5 bar on the green zone, then firmly close both valves.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
  • Filling loop

Related codes

Full explanation for Err HJ-09
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