Annual descaling is the essential task, plus cleaning the inlet filter screen, checking venting, and verifying flow sensors and igniters. In Albuquerque’s hard water, descaling is what determines whether a tankless unit reaches twenty years or fails at eight.

Descaling — The Critical One

Tankless units heat water through a compact heat exchanger with narrow passages. Albuquerque’s dissolved calcium and magnesium precipitate onto those surfaces as the water heats, forming scale that insulates the exchanger, restricts flow, and forces the unit to work harder for less output. Left alone, it eventually triggers error codes and heat exchanger failure — the most expensive component in the unit.

Descaling circulates a food-grade descaling solution through the exchanger to dissolve that buildup. Annually is the right interval here; in some homes with especially hard water, more often. Many manufacturers require documented descaling to keep warranty coverage valid.

The Rest of the Checklist

  • Clean the inlet water filter screen. Catches sediment; a clogged screen reduces flow and can mimic a bigger problem.
  • Clean the air intake filter — relevant in a dusty climate.
  • Inspect venting for obstructions, proper slope, and secure connections.
  • Check the igniter, burner, and flame sensor on gas units.
  • Test flow sensors and error history, which often reveals a developing problem before it becomes a failure.
  • Verify gas pressure under full firing load.
  • Inspect the condensate drain and neutralizer on condensing models — that condensate is acidic.

Make It Easier: Isolation Valves

If your unit was installed with isolation (service) valves, descaling is straightforward. If it was not, it is considerably more work. Worth asking about at installation — it is inexpensive then and awkward to add later.

Treat the Cause

A whole-house water softener dramatically slows scaling and protects your fixtures, appliances, and evaporative cooler at the same time. For anyone installing tankless in this metro, it is the single best companion investment.

Care Club members get scheduled service. Contact B. Carlson for tankless maintenance in Albuquerque.