Navien NCB300 Combi LPG Boilers
Compact Power and Efficiency
The Navien NCB300 LPG-ready combi boiler is the ideal choice for homes off the gas grid, offering high performance, efficiency, and reliability in a compact design. Supplied with an LPG conversion kit as standard, it delivers powerful heating and consistent hot water comfort for smaller homes, rural properties, and holiday lets.
- LPG
- Combi
The Navien NCB300 combines efficiency, reliability, and smart technology in a compact design. With extended venting up to 8 metres and compatibility with LPG and natural gas (conversion kit included), it offers flexible installation for a variety of homes.
Enjoy A+ energy efficiency for ultra-low running costs, plus smartphone control, weather forecasting, and geofencing for effortless comfort and convenience. Built with stainless steel heat exchangers and hydrogen-ready (20% blend) technology, it’s engineered for long-term durability and future sustainability — all backed by a 5-year parts and labour warranty for total peace of mind.
The Navien NCB300 Series delivers outstanding efficiency, compact design, and reliable performance across four models — 28kW, 30kW, 37kW, and 41kW. Each model is engineered to meet different home heating and hot water demands, offering flexible installation options and long-lasting durability. Whether you need consistent hot water for one shower or a system that supports multiple outlets, there’s an NCB300 to suit your property perfectly.
| Model | NCB300-28K | NCB300-30K | NCB300-37K | NCB300-41K |
|---|---|---|---|---|
| Shower Rating | 1 shower | 1 shower + 1 tap | 2 showers | 2 showers + 1 tap |
| Heat Input Range (kW) | 24.7 / 4.3 | 24.7 / 4.3 | 26.8 / 4.6 | 26.8 / 4.6 |
| Modulation Ratio (CH) | 6:1 | 6:1 | 6:1 | 6:1 |
| CH Output Range @ 80/60°C (kW) | 24.0 / 4.2 | 24.0 / 4.2 | 26.0 / 4.5 | 26.0 / 4.5 |
| DHW Heat Input Range (kW) | 28.0 / 4.3 | 30.0 / 4.3 | 37.0 / 4.6 | 41.0 / 4.6 |
| DHW Output Range (kW) | 28.0 / 4.3 | 30.0 / 4.3 | 37.0 / 4.6 | 41.0 / 4.6 |
| DHW Flow Rate @ 25°C Rise | 16.0 l/min | 17.2 l/min | 21.3 l/min | 23.6 l/min |
| DHW Flow Rate @ 35°C Rise | 11.5 l/min | 12.3 l/min | 15.2 l/min | 16.8 l/min |
| DHW Flow Rate @ 45°C Rise (Kitchen) | 9.0 l/min | 9.6 l/min | 11.8 l/min | 13.1 l/min |
| TDR (Total Modulation Ratio) | 7:1 | 7:1 | 8:1 | 9:1 |
| Flue System | Coaxial Ø60/100mm | Coaxial Ø60/100mm | Coaxial Ø60/100mm | Coaxial Ø60/100mm |
| Max. Horizontal Flue Length | 8m | 8m | 8m | 8m |
| Max. Vertical Flue Length | 8m | 8m | 8m | 8m |
| Lift Weight | 29kg | 29kg | 33kg | 33kg |
| Dimensions (W x D x H) | 395 × 285 × 680mm | 395 × 285 × 680mm | 395 × 285 × 680mm | 395 × 285 × 680mm |
| ErP Efficiency Rating | A (93%) | A (93%) | A (93%) | A (93%) |
| ErP Efficiency with Smart Plus (x3) | A+ (98%) | A+ (98%) | A+ (98%) | A+ (98%) |
| NOx Classification | Class 6 | Class 6 | Class 6 | Class 6 |
All NCB300 models feature stainless steel heat exchangers, hydrogen-ready (20% blend) technology, and a 5-year parts and labour warranty — ensuring long-term reliability, lower emissions, and future-ready efficiency.
Compact, high-performance design – perfect for smaller homes and apartments.
ErP A+ rated efficiency – ultra-low running costs and reduced emissions.
Smart control ready – remote operation, geofencing, and weather forecasting.
Hydrogen-ready (20% blend) – futureproof for cleaner energy.
Stainless steel heat exchangers – durable and highly efficient.
5-year parts & labour warranty – reliable performance you can trust.
What’s Included with The Boiler Team Installation?
- Installed by a local Gas Safe engineer
- Old boiler & tanks removed (if applicable)
- All waste cleared, including the old boiler
- Flue installation for optimal performance
- Magnetic filter to protect your system
- System cleanse + protective treatments included
- Pipework upgrades were required
- Premium copper & fittings supplied
- Electrical setup, including wireless thermostat (if applicable)
- Delivery & setup arranged for you
- Warranty registration & certification handled
- Manufacturer parts & labour warranty included
- 10-Year workmanship guarantee from The Boiler Team
Frequently Asked Questions About Navien Boilers
Find clear, expert answers about Navien LPG combi boilers — discover their features, efficiency benefits, and how to choose the best gas boiler for your home.
The Navien NCB300 is a compact, high-efficiency gas condensing combi boiler offering instant hot water and reliable heating. Available in 28kW, 30kW, 37kW, and 41kW versions, it’s designed for small to medium homes that demand performance, efficiency, and space-saving design.
Yes — the NCB300 is LPG-compatible and includes a conversion kit as standard. It’s perfect for homes off the gas grid, providing the same exceptional efficiency, comfort, and reliability as the natural gas version.
The NCB300 comes in four output levels:
28kW – one shower
30kW – one shower + one tap
37kW – two showers
41kW – two showers + one tap
Choose the model that best matches your household’s hot water demand.
Rated ErP A (93%), the NCB300 achieves A+ (98%) efficiency when paired with Navien Smart Plus controls — ensuring low running costs and reduced emissions.
Yes — it’s hydrogen-ready up to 20% blend, futureproofing your heating system for next-generation, low-carbon fuels.
Absolutely. The NCB300 is compatible with Navien Smart Control, allowing you to adjust heating and hot water remotely from your smartphone. It also features weather forecasting and geofencing for smarter energy use.
Extremely quiet. The boiler’s advanced stainless steel heat exchangers and high-quality components ensure low-noise operation, making it ideal for kitchens, flats, or open-plan living spa
The Navien NCB300 includes a 5-year parts and labour warranty as standard — guaranteeing long-term reliability and peace of mind.
With its compact 395 × 285 × 680mm size and extended flue options up to 8m, the NCB300 offers flexible installation in cupboards, utility rooms, or wall-mounted configurations
Because it combines premium performance, LPG compatibility, and smart-ready technology in a compact, affordable package. The NCB300 delivers the reliability and build quality expected from a top-tier boiler brand — at an entry-level price.
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