Eric Aune, licensed master plumber in Minnesota, walks through the process of flushing and descaling a tankless water heater — a maintenance task that's simpler and more affordable than most homeowners assume. The setup requires just a few items: a small transfer pump, a bucket, hoses, and a citric acid-based descaler like CalciFree. The solution circulates through the unit's heat exchanger for about 20 minutes, loosening mineral and calcium buildup, followed by a clean-water flush before the system goes back online. Eric advises against vinegar — it's too diluted to be effective and rarely manufacturer-approved — and notes that depending on local water hardness, descaling may be needed more than once a year. A basic DIY kit can be assembled for under $125.

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