Navien publishes installation and owner manuals on navieninc.com under each model's product page. Plus the printed installation manual ships in the box. Owner manuals are also accessible in the NaviLink app.
Where to download
- navieninc.com — search by model number; download the Installation & Operation Manual plus Owner Manual
- NaviLink app — paired units show manuals in the Help section
- Navien customer service — 1-800-519-8794. They will email any manual if you have the serial number
Documents you might need
- Installation Manual — for the installer. Gas line sizing, venting tables, condensate plumbing, electrical, commissioning. Required reference for warranty work
- Owner Manual — controller operation, temperature, recirculation, basic troubleshooting
- Parts Diagram — exploded view, every part numbered. Required for ordering parts
- Spec Sheet — single-page summary. Used for permits
- For combi boilers: Hydronic Piping Guide — Navien-specific primary/secondary loop diagrams. Critical for proper combi install
- For commercial: Cascade Installation Manual — for multi-unit installs
Manuals by line
- NPE-A2 / S2 — single master manual for both trims
- Legacy NPE-A / NPE-S — archived on navieninc.com under Legacy Products
- NCB combi boilers — NCB-240, NCB-180E, NCB-210E etc. share one manual with model-specific spec tables
- NFC fire-tube combi — its own dedicated installation manual
- NHB boilers — NHB-55 through NHB-150 share one manual
- NPN non-condensing — its own installation manual
Bottom line
For combi boiler installs especially, always use the model-specific Installation Manual and the Hydronic Piping Guide together. Generic hydronic boiler guidance is not a substitute — Navien's primary/secondary loop requirements are specific to the unit.