I live in a three-story townhouse and I have a Navien tankless water heater installed in my first floor garage. When I turn on hot water on the first floor, I’m able to get hot water pretty quickly, in 10 seconds or so.
However, when I do the same on the second and third floor, it takes extremely long to get hot water (sometimes up to a minute). What could be a possible reason for this? Water in my area is extremely hard, and I haven’t been using a proper water soften. Could this have clogged a pipe going to second and third floor for hot water? Water pressure for both hot and cold water is great on both floors, so I’m not sure if this is water heater or pipes. I haven’t flushed the water heater for the past three years, if this helps.
I feel the delay has become worse in the pst two years. Any help would be greatly appreciated!