Watch for longer startup times, noisy burner ramping, fluctuating outlet temps, frequent resets

https://pub-a3d0921cc64d4b5c8a08eea958469665.r2.dev/tankless-water-heater-repair/what-358-mgl-hard-water-does-to-boerne-tankless-heaters.html

Watch for longer startup times, noisy burner ramping, fluctuating outlet temps, frequent resets, and rising gas use; these early signs in Boerne typically trace to scale buildup choking sensors and passages.