Case study

Ökoboiler: decoding the water heater's internal UART bus

The Ökoboiler study reconstructs the single-wire UART exchange between a heat-pump water heater's display and control boards. It documents 32-byte frames, XOR masking, CRC-16/Modbus and fields for tank temperature, operating mode and PV state, with a Python decoder and an ESPHome sensor configuration.

Targets: Protocol
Category: Independent reconstruction cases
Relationship: Independent reconstruction project
Sources reviewed: 2026-11-06
Evidence class: C2 code & docs, no demo or download

Stars: 9
Last commit: 2026-07-09
Language: Python
License (GitHub): MIT

GitHub data as of 2026-11-10

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Evidence

Observed: Code, documentation and a demo observed; no download method found.
Checked: 2026-11-09

How evidence classes are assigned

Requirements & limits

Prerequisites: The documented capture setup uses an Ökoboiler unit and an ESP32-C6 running ESPHome.
Limits: The author reports validating the protocol on one unit over several days of traffic.
License: MIT licence.

Cite

BibTeX

@misc{oekoboiler-uart-case,
  title = {{Ökoboiler: decoding the water heater's internal UART bus}},
  howpublished = {\url{https://github.com/splattner/oekoboiler-uart-reverse-engineering}},
  url = {https://github.com/splattner/oekoboiler-uart-reverse-engineering},
  urldate = {2026-11-06},
  note = {Awesome REA entry: \url{https://awesomerea.org/resources/oekoboiler-uart-case/}}
}

Plain text

Ökoboiler: decoding the water heater's internal UART bus. https://github.com/splattner/oekoboiler-uart-reverse-engineering (accessed 2026-11-06). Awesome REA entry: https://awesomerea.org/resources/oekoboiler-uart-case/

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About this entry

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Primary sources

PROTOCOL.md GitHub · splattner/oekoboiler-uart-reverse-engineering · Revision 8a164da
README.md GitHub · splattner/oekoboiler-uart-reverse-engineering · Revision 8a164da
scripts/README.md GitHub · splattner/oekoboiler-uart-reverse-engineering · Revision 8a164da