Navien NCB700 2S+/42K 42kW Combi Boiler Internal Compact Hydrogen Ready with Built-In DHW Recirculation
Navien NCB700 2S+/42K 42kW Combi Boiler delivers 17.2 LPM DHW flow, built-in recirculation pump, 10:1 turndown ratio, and 94% ErP efficiency—engineered for high-demand, future-ready performance.
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The Navien NCB700 2S+/42K 42kW Combi Boiler is built to meet the needs of larger homes with multiple bathrooms and high hot water usage. With a DHW flow rate of 17.2 LPM at a 35°C rise, it can comfortably supply three bathrooms simultaneously—a market-leading feature in combi boiler technology.
Equipped with a built-in DHW recirculation pump and NaviCirc return system, this boiler ensures instant hot water delivery and minimal water wastage. Its ASME-certified stainless steel heat exchangers guarantee reliability and long-term performance.
Featuring hydrogen-ready technology (20% blend) and a 10:1 turndown ratio, the NCB700 delivers efficient, eco-conscious performance tailored to real-time demand. The digital display with a setup wizard simplifies installation, while compatibility with Smart Plus thermostats allows for ErP A+ efficiency.
With a 94% ErP efficiency rating and 12-year warranty, this combi boiler combines powerful heating performance with durability and sustainability—ideal for modern, high-spec households.
Key Features
Industry-Leading Flow Rate – Delivers 17.2 LPM at 35°C rise to supply up to 3 bathrooms at once
Built-In DHW Recirculation Pump – Minimizes water waste and ensures instant hot water
ASME-Certified Stainless Steel Heat Exchangers – Long-term durability with maximum efficiency
10:1 Turndown Ratio – Smart modulation reduces energy waste and maintains precise output
Hydrogen Ready – Supports 20% hydrogen blend for a sustainable future
NaviCirc Return System – Integrated hot water return solution reduces lag and enhances efficiency
Digital Display & Setup Wizard – Simplifies configuration and operation
High Efficiency – 94% ErP rating and A+ rating with Smart Plus thermostat pairing
12-Year Warranty – Exceptional manufacturer-backed peace of mind
Applications
Multi-Bathroom Homes – Ideal for households needing simultaneous hot water access
Modern Smart Heating Systems – Easily integrates into advanced multi-zone setups
Eco-Conscious Properties – Hydrogen-ready and recirculation-equipped for water and energy savings
Technical Specifications:
| Feature | Details |
|---|---|
| Product Name | Navien NCB700 2S+/42K 42kW Combi Boiler |
| Model Number | PNCB7000042L001 |
| Fuel Type | Natural Gas / LPG |
| Heat Output (CH) | 42 kW |
| DHW Output (Min/Max) | 3.5 / 42.0 kW |
| DHW Flow Rate (35°C Rise) | 17.2 l/min |
| CH Condensing Max Output | 37.1 kW |
| ERP Rating | A (A+ with Smart Plus thermostats) |
| Noise Level | 51 dBA |
| Max Vertical Flue (125mm) | 70 meters |
| Max Vertical Flue (100mm) | 21 meters |
| Max Horizontal Flue (100mm) | 21 meters |
| NOx Class | 6 |
| Solar Compatible | Yes |
| Dimensions | 695mm (H) × 440mm (W) × 353mm (D) |
| Warranty | 12 Years |
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