Navien LCB700 21kW External Oil System Boiler | Boilerhut

Navien LCB700 21kW External Oil System Boiler

Price: £2,337    each, inc. VAT | Ex. installation | 3-10 years finance available.

The Navien LCB700 21kW oil system boiler is an excellent choice for those who require a high level of hot water and heating for their homes. These boilers are built to last and come with stainless steel heat exchangers, which we really appreciate. Additionally, they are one of the only boiler models that use Blue Flame technology.

If you are considering the Navien LCB700 for your next oil system boiler, below is a quick review and technical specification to help you get as much information as possible.

  • Heat output: 21kW
  • Stainless Steel Heat Exchanger
  • 10 Year Warranty

(Boiler-only price: comparing five or more suppliers, including Screwfix and Plumbase. Correct February 2024).

The Navien LCB700 21kW Oil System Boiler is a modern condensing boiler with a high efficiency of 93%. It offers a range of innovative and technologically advanced features. For example, Blue Flame technology gives superior efficiency and guarantees low NOx emissions.

Navien LBC700 Stainless Steel Heat Exchanger

Navien LBC700 21kW Stainless Steel Heat Exchanger.


  • 93% / A rated efficiency
  • Stainless steel heat exchanger, making it highly efficient and durable
  • Hydrated Vegetable Oil (HVO) compatible
  • Get a premium oil system boiler at a great price.
  • 10-year warranty
  • Modulation rage of 1:10
  • Also available in an internal version and available in 28kW and 36kW system boiler versions

Size and Installation

  • External version of the LCB700; heavily insulated and protected
  • 21kW oil condensing system boiler
  • Integrated expansion vessel


  • Easy to use controls
  • 3-zone ready – control up to 3-zones out-of-the-box
  • Smart thermostat compatible such as Tado and controlled via a smartphone

Environmentally Friendly

  • Blue Flame technology burns fuel at a higher temperature, resulting in fewer emissions
  • Low NOx emissions for reduced environmental impact
  • 1:10 modulation enables running at reduced power output
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