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Navien · Tankless water heater

E760 Flushing / service alarm

Low severity Navien NPE-2

What the control is telling you

Service reminder: the scheduled service or descaling interval has run out.

Applies to: Navien NPE-A2 (built-in recirculation) and NPE-S2 condensing tankless water heaters: NPE-150S2, NPE-180A2/S2, NPE-210A2/S2, NPE-240A2/S2

Likely causes

  • Service notification time reached (default 1,820 days)
  • Descaling reminder interval reached

Test and repair steps

  1. Perform routine service flush the heat exchanger and clean the inlet water, recirculation inlet and air intake filters.
  2. Check water hardness and recommend a softener or PeakFlow if above 7 grains/gal.
  3. Adjust the interval if needed Installer Menu > 4. Service Notif Time (0-3,650 days) or Parameter 13. Descaling Reminder (No Alarm/6/12/24 months).
  4. Reset with the Back button after service.

Settings for these units

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Source: Navien NPE-A2/S2 User's Information Manual (20049624A), 5.2 Understanding Error Codes, p.18. Summarized in our own words; check the original manual for your model.

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For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.