Rule Compliance and Reverse Engineering of Smart Boiler Control Logic: A Telemetry-Based Feasibility Study

<jats:p>This study examines whether the boiler-control rules documented for a smart central heating automation project can be verified, and partly reconstructed, from operational field telemetry. The material includes 865,000 telemetry records collected from 11 boilers across 10 sites between September 2025 and January 2026, together with site metadata and boiler configuration tables. The analysis focuses on seven rule families: outdoor-temperature-based heating shutdown, cold-weather maximum set point use, intermediate set point behavior, Status hysteresis, domestic-hot-water auxiliary signals, main-boiler outdoor-temperature sharing and heating-station offset behavior. Rule compliance is evaluated through direct conditional tests, boiler-level stratification, transition-event analysis and signal-consistency checks. The results show strong evidence for the outdoor-temperature shutdown rule: when outdoor temperature exceeded 15 °C, the general off-state ratio reached 99.90%. However, this behavior was not equally strict across all boilers, as Boiler 50 had a lower warm-off ratio of 65.85%. In contrast, the rule that very cold outdoor conditions should trigger the configured MaxTemperature set point could not be confirmed because the observed SettedTemperature values did not match the configured MaxTemperature values. Reverse engineering of Status transitions yielded meaningful hysteresis bands for several core boilers, showing that on/off behavior can be inferred at the behavioral level. At the same time, ThreeWayValveStatus, BoilerStatus and PumpStatus displayed semantic inconsistencies. The findings therefore support the use of the dataset for explainable behavioral rule extraction and offline replay simulation, while also showing that exact PLC parameter validation requires additional register-level semantic verification.</jats:p>