{"product_id":"navien-lcb700-21kw-rs-internal-regular-oil-boiler-lcb700-21rs","title":"Navien LCB700 21kW RS Internal Regular Oil Boiler - LCB700-21RS","description":"\u003ch2\u003eNavien LCB700 21kW RS Internal Regular Oil Boiler - LCB700-21RS\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eNavien LCB700 21kW RS Internal Regular Oil Boiler\u003c\/strong\u003e is a high-efficiency condensing oil boiler designed for internal installation in domestic heating systems.\u003c\/p\u003e\n\n\u003cp\u003ePart of Navien's innovative \u003cstrong\u003eLCB700 range\u003c\/strong\u003e, the LCB700-21RS combines advanced blue flame combustion technology, a durable stainless-steel heat exchanger and flexible installation options to provide efficient, dependable oil-fired central heating.\u003c\/p\u003e\n\n\u003cp\u003eWith a two-stage heat output of \u003cstrong\u003e16kW \/ 21kW at 80\/60°C\u003c\/strong\u003e and up to \u003cstrong\u003e23.0kW at 50\/30°C\u003c\/strong\u003e, this model is designed for properties requiring a compact regular oil boiler with excellent efficiency and low emissions.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eNavien LCB700 internal regular oil boiler\u003c\/li\u003e\n  \u003cli\u003eModel: \u003cstrong\u003eLCB700-21RS\u003c\/strong\u003e\n\u003c\/li\u003e\n  \u003cli\u003eMaximum heat output: \u003cstrong\u003e21kW\u003c\/strong\u003e\n\u003c\/li\u003e\n  \u003cli\u003eTwo-stage 16kW \/ 21kW heat output at 80\/60°C\u003c\/li\u003e\n  \u003cli\u003eUp to 23.0kW output at 50\/30°C\u003c\/li\u003e\n  \u003cli\u003eCondensing blue flame oil boiler technology\u003c\/li\u003e\n  \u003cli\u003eErP A-rated boiler\u003c\/li\u003e\n  \u003cli\u003e93% ErP efficiency\u003c\/li\u003e\n  \u003cli\u003eCan achieve A+ system efficiency when combined with qualifying Navien Smart Plus controls\u003c\/li\u003e\n  \u003cli\u003eHVO compatible\u003c\/li\u003e\n  \u003cli\u003eStainless-steel heat exchanger\u003c\/li\u003e\n  \u003cli\u003eUltra-low NOx combustion technology\u003c\/li\u003e\n  \u003cli\u003e57.2mg\/kWh NOx emission rate\u003c\/li\u003e\n  \u003cli\u003eCompact internal design\u003c\/li\u003e\n  \u003cli\u003eText-driven integral display\u003c\/li\u003e\n  \u003cli\u003eDisplays boiler operating and fuel consumption information\u003c\/li\u003e\n  \u003cli\u003e3-zone ready when used with Navien Smart Plus control pack\u003c\/li\u003e\n  \u003cli\u003eFlexible pipework arrangements\u003c\/li\u003e\n  \u003cli\u003eCombined PRV \/ condensate drainage design\u003c\/li\u003e\n  \u003cli\u003e60\/100mm coaxial plastic flue system\u003c\/li\u003e\n  \u003cli\u003eMaximum horizontal flue length up to 20 metres\u003c\/li\u003e\n  \u003cli\u003eMaximum vertical flue length up to 21 metres\u003c\/li\u003e\n  \u003cli\u003e10-year parts and labour warranty as standard, subject to Navien terms\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specification\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Navien\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRange:\u003c\/strong\u003e LCB700\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e LCB700-21RS\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Internal Regular Oil Boiler\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBoiler Type:\u003c\/strong\u003e Condensing Regular \/ Heat Only Boiler\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInstallation Location:\u003c\/strong\u003e Internal\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFuel Type:\u003c\/strong\u003e Heating Oil \/ Kerosene\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHVO Compatible:\u003c\/strong\u003e Yes\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeat Input Stage 1 \/ Stage 2:\u003c\/strong\u003e 17kW \/ 22kW\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeat Output at 80\/60°C:\u003c\/strong\u003e 16kW \/ 21kW\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Heat Output at 50\/30°C:\u003c\/strong\u003e 23.0kW\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eErP Energy Rating:\u003c\/strong\u003e A\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eErP Efficiency:\u003c\/strong\u003e 93%\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePotential System Rating:\u003c\/strong\u003e Up to A+ with qualifying Smart Plus control configuration\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNOx Emissions:\u003c\/strong\u003e 57.2mg\/kWh\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeat Exchanger:\u003c\/strong\u003e Stainless Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlue Type:\u003c\/strong\u003e Coaxial Plastic\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlue Size:\u003c\/strong\u003e 60\/100mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Horizontal Flue Length:\u003c\/strong\u003e 20m\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Vertical Flue Length:\u003c\/strong\u003e 21m\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e90° Flue Elbow Equivalent:\u003c\/strong\u003e 1.3m\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCentral Heating Flow Connection:\u003c\/strong\u003e 22mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCentral Heating Return Connection:\u003c\/strong\u003e 22mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOil Supply:\u003c\/strong\u003e 1\/4\" BSP\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCondensate Connection:\u003c\/strong\u003e 21.5mm minimum\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 470mm W x 600mm D x 860mm H\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNet Weight:\u003c\/strong\u003e 58kg\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eControl Display:\u003c\/strong\u003e Integral text-driven display\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSmart Control Compatibility:\u003c\/strong\u003e Navien Smart Plus\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeating Zones:\u003c\/strong\u003e Up to 3 zones with compatible Smart Plus controls\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 10-year parts and labour warranty, subject to manufacturer terms\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHigh Efficiency Blue Flame Technology\u003c\/h3\u003e\n\n\u003cp\u003eThe Navien LCB700 incorporates advanced \u003cstrong\u003eblue flame combustion technology\u003c\/strong\u003e designed to deliver efficient oil combustion while keeping NOx emissions low.\u003c\/p\u003e\n\n\u003cp\u003eThe LCB700-21RS achieves an \u003cstrong\u003eErP A rating with 93% efficiency\u003c\/strong\u003e. When incorporated into a qualifying heating system using Navien Smart Plus controls, the system can achieve an A+ rating.\u003c\/p\u003e\n\n\u003ch3\u003e21kW Two-Stage Heating Performance\u003c\/h3\u003e\n\n\u003cp\u003eThe LCB700-21RS operates at two heating stages, providing approximately \u003cstrong\u003e16kW and 21kW output at 80\/60°C\u003c\/strong\u003e. At lower-temperature condensing conditions of 50\/30°C, maximum output increases to approximately \u003cstrong\u003e23.0kW\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003eThis two-stage design allows the boiler to better respond to changing heating demand compared with a simple fixed-output appliance.\u003c\/p\u003e\n\n\u003ch3\u003eHVO Compatible\u003c\/h3\u003e\n\n\u003cp\u003eNavien lists the LCB700 range as \u003cstrong\u003eHVO compatible\u003c\/strong\u003e, helping provide greater flexibility as the heating industry transitions towards lower-carbon liquid fuel alternatives.\u003c\/p\u003e\n\n\u003cp\u003eFuel suitability, burner setup and any conversion or commissioning requirements should always be confirmed by a qualified oil heating engineer and carried out in accordance with current Navien instructions.\u003c\/p\u003e\n\n\u003ch3\u003eStainless-Steel Heat Exchanger\u003c\/h3\u003e\n\n\u003cp\u003eThe LCB700 features a durable \u003cstrong\u003estainless-steel heat exchanger\u003c\/strong\u003e designed to provide long-term performance and efficiency in a condensing oil boiler application.\u003c\/p\u003e\n\n\u003ch3\u003eFlexible Flue Installation\u003c\/h3\u003e\n\n\u003cp\u003eThe Navien LCB700 uses a \u003cstrong\u003e60\/100mm coaxial plastic flue system\u003c\/strong\u003e and offers unusually long flue capabilities for flexible installation.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eMaximum horizontal flue length: up to 20m\u003c\/li\u003e\n  \u003cli\u003eMaximum vertical flue length: up to 21m\u003c\/li\u003e\n  \u003cli\u003e90° elbow equivalent deduction: approximately 1.3m\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eActual permitted flue length depends on the complete approved flue arrangement, number of bends and Navien installation instructions.\u003c\/p\u003e\n\n\u003ch3\u003eSmart Plus Controls\u003c\/h3\u003e\n\n\u003cp\u003eThe LCB700 is compatible with Navien's \u003cstrong\u003eSmart Plus control system\u003c\/strong\u003e. When correctly configured, Smart Plus can provide multi-zone heating control, with the LCB700 capable of supporting up to three heating zones.\u003c\/p\u003e\n\n\u003cp\u003eA qualifying Smart Plus control configuration can also increase the overall system energy rating from ErP A to \u003cstrong\u003eErP A+\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eRegular Boiler Installation\u003c\/h3\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eLCB700-21RS is a regular \/ heat-only boiler\u003c\/strong\u003e. It does not provide instantaneous domestic hot water in the same way as a combination boiler.\u003c\/p\u003e\n\n\u003cp\u003eWhere domestic hot water is required, the boiler is typically incorporated into a heating system using a separate hot water cylinder and the necessary external system components and controls.\u003c\/p\u003e\n\n\u003ch3\u003e10-Year Warranty\u003c\/h3\u003e\n\n\u003cp\u003eNavien currently advertises the LCB700 range with a \u003cstrong\u003e10-year parts and labour warranty as standard\u003c\/strong\u003e, subject to installation, commissioning, registration, servicing and all applicable Navien warranty terms.\u003c\/p\u003e\n\n\u003ch3\u003eImportant Product Information\u003c\/h3\u003e\n\n\u003cp\u003eThis product is the \u003cstrong\u003eNavien LCB700-21RS 21kW Internal Regular Oil Boiler\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDo not confuse this model with the LCB700-21LS System Boiler, LCB700-21LC Combi Boiler or the external LCB700-21RSX version.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFlue kit, hot water cylinder, heating controls, system components, oil line components, filters, valves, chemicals and installation accessories are not included unless specifically stated elsewhere in the listing.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch3\u003eProfessional Installation Required\u003c\/h3\u003e\n\n\u003cp\u003eThis oil-fired boiler must be installed and commissioned by a suitably qualified oil heating engineer. In the UK, installation by an \u003cstrong\u003eOFTEC registered technician\u003c\/strong\u003e is recommended.\u003c\/p\u003e\n\n\u003cp\u003eThe installer must confirm boiler sizing, system design, oil supply, fuel type, flue arrangement, condensate disposal, heating controls and combustion settings before commissioning.\u003c\/p\u003e","brand":"Navien","offers":[{"title":"Default Title","offer_id":50557795893504,"sku":"NAVIEN-LCB700-21RS","price":1683.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/2814\/files\/navien-lcb700-rsrsx-blue-flame-internalexternal-regular-oil-boiler-9383754.webp?v=1791455421","url":"https:\/\/spares-direct.com\/products\/navien-lcb700-21kw-rs-internal-regular-oil-boiler-lcb700-21rs","provider":"Spares Direct","version":"1.0","type":"link"}