Navien NCB300 28kW Combi Boiler – Natural Gas / LPG (Includes Flue)

The Navien NCB300 28kW Combi Boiler is a compact yet powerful heating solution designed for smaller to medium-sized homes. As Navien’s entry-level combi, it delivers impressive hot water performance, efficient heating, and flexible installation options—all within a cupboard-fit design.

Built with stainless steel heat exchangers, the NCB300 ensures long-term durability and efficiency. Its 6:1 turndown ratio allows the boiler to modulate output effectively, reducing energy consumption while maintaining consistent comfort.

Hydrogen-ready (20% blend) and compatible with Navien smart tools, this boiler is designed for both current performance and future energy standards. Supplied with a flue, it offers added value and convenience for installation.

Why Customers Should Buy This Product

• 28kW output ideal for small to medium homes
• Includes flue for added convenience and value
• Stainless steel heat exchangers for durability and efficiency
• 6:1 modulation ratio for reduced energy usage
• High hot water flow rate (11.5 l/min) for reliable performance
• Compact cupboard-fit design for flexible installation
• Hydrogen-ready (20% blend) for future-proofing
• Smart compatibility with Navien Service Toolkit
• Lightweight unit for easier installation
• Digital display for simple operation
• 5-year manufacturer’s warranty for peace of mind
• Reliable quality from Navien

Key Specifications

• Brand: Navien
• Range: NCB300
• Model: 28kW Combi
• Product Type: Combi Boiler
• Fuel Type: Natural Gas / LPG
• Mount Type: Wall Mounted

Performance:

• Heat Output: 28 kW
• CH Output (Max): 25.8 kW
• DHW Output: 28 kW
• DHW Flow Rate (35°C rise): 11.5 l/min
• DHW Output Range: 4.3 – 28 kW
• Modulation Ratio: 6:1

Efficiency & Ratings:

• ERP Rating: A (A+ with Smart Plus controls)
• NOx Class: 6

Dimensions:

• Height: 680 mm
• Width: 395 mm
• Depth: 283 mm

Flue Options:

• Max Vertical (125mm): 28 m
• Max Vertical (100mm): 8 m
• Max Horizontal (125mm): 27 m
• Max Horizontal (100mm): 8 m

Design & Features:

• Stainless steel heat exchangers
• Digital display
• Compact cupboard-fit design
• Hydrogen-ready (20% blend)
• Compatible with Navien Smart Service Toolkit

Noise Level:

• 52 dB

Additional Information:

• Flue included

Warranty:

• 5 Years Manufacturer’s Guarantee

What’s in the Box

• 1 x Combi Boiler
• Flue Kit

Important Information

• Must be installed by a Gas Safe registered engineer
• Suitable for sealed systems (no separate hot water cylinder required)
• Controls sold separately