A noticeable drop in hot water temperature from a tankless water heater is usually caused by heavy calcium and lime scale buildup coating the internal heat exchanger coils, a restricted cold water inlet filter screen, or a failing gas control valve. Hard water minerals insulate the heat exchanger tubing, drastically reducing thermal transfer efficiency. Verification: Inspect and clean the inlet water filter screen, and flush the heat exchanger with a descaling vinegar solution.
1 votes
Marked as accepted