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Navien · Tankless water heater

E031 Burner overheating

Critical severity Navien NPE-2

What the control is telling you

The burner high-temperature protection tripped.

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

  • Burner overheat (burner high limit fuse)
  • Combustion or air supply problem

Test and repair steps

  1. Warning: do not keep resetting a burner overheat - check the cause first.
  2. Inspect the intake and exhaust for blockage and clean the air intake filter.
  3. Check CO2 at low and high fire against the table in the installation manual (Appendix 8.1).
  4. Only fix given phone Navien Technical Support, 1-800-519-8794.

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Source: Navien NPE-A2/S2 User's Information Manual (20049624A), 5.2 Understanding Error Codes, p.17. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

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.