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Condensing tankless water heater

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Navien Condensing tankless water heater NPE-S2 Series

Navien Water heating products Condensing tankless water heater Repair, maintenance, and replacement planning
Navien NPE-S2 Series product image

Technical Specifications

Product Specs

  • Brand: Navien
  • Model or series: NPE-S2 Series
  • Equipment type: Condensing tankless water heater
  • Product group: Water heating products
  • Condensing tankless water heater equipment
  • tankless water heater
  • combi boiler
  • Condensing tankless water heater equipment for hot water complaints
  • System role: Water-heating equipment for domestic or commercial hot-water loads
  • Application: Domestic or commercial hot-water applications when model capacity is appropriate
  • Compatibility check: Verify fuel type, venting, electrical requirements, capacity, controls, and installation clearances.
  • Verified source: navieninc.com

Useful troubleshooting details

  • Confirm the exact NPE-S2 Series model number, serial number, capacity, voltage, refrigerant or fuel type, controls, and matched equipment.
  • Share current symptoms, alerts or error codes, recent maintenance, access notes, and whether the issue is urgent or planned.
  • For replacement planning, note comfort goals, existing equipment age, and any heat-pump, electrification, or rebate-related questions.

Troubleshooting

Error Codes

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E003 Combustion / venting

Ignition failure

Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service.
E004 Combustion / venting

False flame detection

Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service.
E012 Combustion / venting

Flame loss

Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service.
E016 Equipment control

Heat exchanger overheat

Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service.
E030 Combustion / venting

Exhaust overheat

Record the Navien code, avoid repeated reset attempts, and schedule GreenFlow service.
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Service planning

How GreenFlow handles NPE-S2 Series requests

1

Identify the equipment

Confirm the model or series name, serial number if available, photos, and whether the unit is roof, exterior, basement, or mechanical-room equipment.

2

Describe the service issue

Share no heat, no cooling, weak airflow, error codes, alarms, leaks, noise, control problems, or comfort complaints.

3

Review access and history

Include access notes, tenant or business-hour constraints, filter status, recent repairs, and maintenance records when available.

4

Plan the next step

GreenFlow can route the request for diagnostics, repair planning, maintenance, replacement scope, or related system upgrades.

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Our Happy Customers

Ray

Just had a service call because my tankless water heater stopped working with E110 code. Andrey located the root cause real quick and fixed the issue within half an hour, also gave reasonable recommendations for further maintenance.

Anna G.

They quickly identified the issue with the heating system and fixed it efficiently. He explained everything clearly and made sure I understood what was going on. Very professional and reliable, extremely satisfied with the service.

Neal V.

In an industry that often fraught with contractors taking advantage of homeowners, Andrey was honest with his assessment and willing to install a product acquired elsewhere (most want that margin themselves), patiently answered my questions (I’m an engineer so like to understand what’s happening), and proactively offered practical...

Dev W.

I had a breakdown of my cooling system and Hanna at Green Flow responded to my request right away. They scheduled me same day. The team at Green Flow was easy to communicate with over phone and text. They kept me updated on delays on arrival of the...

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