Navien LCB700 Blue Flame Regular Boiler – External Model
The Navien LCB700 Blue Flame Regular Boiler (External Model) redefines oil-fired heating with its A+ energy efficiency rating — the first of its kind in the UK. Designed for outdoor installation, this advanced boiler combines innovative Blue Flame technology with smart control compatibility to deliver outstanding performance, lower emissions, and reduced running costs.
- Oil
- System
HVO Compatible – Ready for renewable heating fuels, making it a sustainable choice for the future.
10-Year Warranty – Enjoy total peace of mind with Navien’s trusted reliability and engineering quality.
Blue Flame Technology – Delivers exceptional efficiency with ultra-low NOx emissions for cleaner combustion.
Compact & Lightweight Design – Easy outdoor installation with flexible flueing options up to 21m.
Durable Stainless Steel Heat Exchangers – Built for long-lasting performance and reduced maintenance.
Smart Plus Ready – Upgrade to A+ efficiency and manage up to three heating zones with intelligent controls.
User-Friendly Display – Simple, text-driven interface for easy monitoring and energy management.
Modern, Weatherproof Design – Sleek, durable casing ensures reliable performance in all conditions.
Class-Leading Efficiency – A-rated boiler that helps lower running costs and energy usage.
| Specification | 21kW Model | 28kW Model | 36kW Model |
|---|---|---|---|
| Heat Output (80/60°C) | 16–21kW | 21–28kW | 29–36kW |
| Heat Output (50/30°C) | 23.0kW | 30.3kW | 39.0kW |
| Flue Size | Coaxial Plastic Ø60/100 | Coaxial Plastic Ø60/100 | Coaxial Plastic Ø60/100 |
| Max. Horizontal Flue Length | 20m | 20m | 20m |
| Max. Vertical Flue Length | 21m | 21m | 21m |
| Dimensions (HxWxD) | 860 x 600 x 470mm | 860 x 600 x 470mm | 860 x 600 x 470mm |
| Weight (Regular Model) | 58kg | 62kg | 68kg |
| Weight (System Model) | 66kg | 70kg | 76kg |
| ErP Efficiency Rating | A (93%) | A (93%) | A (93%) |
| ErP Efficiency with Smart Plus | A+ (98%) | A+ (98%) | A+ (98%) |
| NOx Emissions | 57.2mg/kWh | 62.5mg/kWh | 63.2mg/kWh |
| NOx Classification | Class 6 | Class 6 | Class 6 |
| Fuel Compatibility | HVO & Kerosene | HVO & Kerosene | HVO & Kerosene |
| Technology | Blue Flame | Blue Flame | Blue Flame |
| Installation Type | External | External | External |
| Weather Protection | IPX4 rated | IPX4 rated | IPX4 rated |
A+ Energy Efficiency – One of the UK’s most efficient oil boilers, helping reduce energy bills and carbon footprint.
HVO Compatible – Ready for renewable heating fuels to support a more sustainable future.
Blue Flame Technology – Ensures cleaner combustion, ultra-low NOx emissions, and superior performance.
External Installation Ready – Durable, weatherproof casing designed for reliable outdoor operation.
Compact & Lightweight Design – Easy to install with flexible flueing options up to 21 metres.
Stainless Steel Heat Exchangers – Built for long-term durability and high corrosion resistance.
Smart Plus Control Ready – Boosts efficiency up to A+ (98%) with intelligent zoning and energy management.
10-Year Warranty – Comprehensive parts and labour cover for complete peace of mind.
Quiet & Reliable Operation – Engineered for smooth, efficient performance in any weather.
Future-Proof Heating Solution – Designed to meet today’s standards and tomorrow’s sustainability goals.
What’s Included with The Boiler Team Installation?
Installed by a local Oftec engineer
Oil Filters / Fire Valve Upgrade Pack Included
Old boiler & tanks removed (if applicable)
All waste cleared, including old boiler
Flue installation for optimal performance
Magnetic filter to protect your system
System cleanse + protective treatments included
Pipework upgrades where 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 Oil Regular boilers — discover their features, efficiency benefits, and how to choose the best gas boiler for your home.
The Navien LCB700 Blue Flame Regular Boiler (External Model) is a high-efficiency, oil-fired heating system designed for outdoor installation. It uses advanced Blue Flame technology to deliver ultra-low NOx emissions and top-tier energy performance.
Yes. The external model is built with a robust, weatherproof casing (IPX4 rated) to ensure reliable operation in all conditions.
The LCB700 is ErP A-rated (93%), and when paired with Navien Smart Plus controls, it can achieve A+ efficiency (up to 98%) for even lower running costs.
Yes, it’s fully compatible with HVO (Hydrotreated Vegetable Oil), making it a future-ready and eco-friendly heating solution.
This model comes in 21kW, 28kW, and 36kW options, allowing homeowners to choose the ideal size for their property and heating needs.
Navien’s Blue Flame system delivers cleaner combustion, higher efficiency, and lower emissions compared to standard yellow-flame burners, making it more eco-conscious and cost-effective.
Yes, every LCB700 Regular Boiler includes a 10-year parts and labour warranty, giving you confidence and long-term peace of mind.
Yes. When connected to Navien’s Smart Plus control pack, you can manage your heating remotely, monitor energy use, and even create up to three heating zones for greater comfort.
It supports flue runs up to 21 metres vertically and 20 metres horizontally, providing exceptional flexibility for outdoor installations.
Yes. With HVO compatibility, ultra-low NOx emissions, and Blue Flame combustion, it’s one of the cleanest and most efficient oil boilers available in the UK.
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