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Navien tankless water heater code E760: Flushing or service reminder

Tankless water heater, Canada and United States

The heater is due for routine service, including flushing the heat exchanger.

This needs a plumber. There is nothing safe to check yourself. Leave the covers on and book a professional.

What causes it

NPE-A/S first-generation condensing models

  1. The heater's service interval has been reached and the heat exchanger needs flushing. Navien's manual says to have the installer carry out routine service.

    Have the heat exchanger flushed and descaled

NPE-A2/S2 condensing models, NPN non-condensing models

  1. The heater's scale or service interval has been reached and the heat exchanger needs flushing. Navien's manual says to have the installer carry out routine service.

    Have the heat exchanger flushed and descaled

How to read this code on your unit

Booking a plumber

Contact Navien before booking a repairYou can do this

  1. Have the model number, serial number, purchase date, where the heater is installed and the error code ready.
  2. Call Navien Technical Support on 1-800-519-8794, or contact the company that installed the heater.
  3. For a repair under warranty, the installer or service provider must contact Navien before starting the work.

Have the heat exchanger flushed and descaledplumber

  1. Scale from hard water builds up inside the heat exchanger and restricts flow and heat transfer.
  2. Book a licensed plumber or the manufacturer's service agent to flush and descale the heat exchanger using the manufacturer's flushing procedure.
  3. Ask about water treatment if you have hard water, so the scale does not come back.

Models that show this code

21 models in 6 ranges
RangeModels
NPE-A (first generation)NPE-180A, NPE-210A, NPE-240A
NPE-S (first generation)NPE-150S, NPE-180S, NPE-210S, NPE-240S
NPE-A2NPE-180A2, NPE-210A2, NPE-240A2
NPE-S2NPE-180S2, NPE-210S2, NPE-240S2, NPE-150S2
NPN-ENPN-120E, NPN-160E, NPN-180E, NPN-199E
NPN-UNPN-160U, NPN-180U, NPN-199U

Where this comes from

Checked against the manufacturer's manual on 9 October 2026.

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Other Navien tankless water heater codes

Code Meaning What you can do
E517 DIP switch setting error Call a pro
E593 Front panel button fault Call a pro
E594 Memory chip (EEPROM) fault Call a pro
E615 Input and memory fault Call a pro
E736 Cascade communication fault Call a pro
E740 Outdoor temperature sensor fault Call a pro
E762 Vent pipe not fully inserted Call a pro
E773 Wrong gas type detected or gas connection fault (depends on model) Call a pro
E782 Main panel communication fault Call a pro
E785 Flow switch or sensor fault Call a pro
E786 Panel connection fault Call a pro
E788 Gas type setting mismatch Call a pro

See all maintenance reminder codes on tankless water heaters across brands.