{"product_id":"navien-ncb700-on-42kw-combi-boiler-pncb7000042l001-12-year-warranty","title":"Navien NCB700 ON 42kW Combi Boiler | PNCB7000042L001 | 12-Year Warranty","description":"\u003c!-- SEO Product Name: Navien NCB700 ON 42kW Combi Boiler | PNCB7000042L001 | 12-Year Warranty --\u003e\n\u003cdiv style=\"font-size:16px; max-width:900px; color:#1a1a1a; line-height:1.6;\"\u003e\n\n  \u003cp style=\"margin:0 0 16px 0;\"\u003eThe \u003cstrong\u003eNavien NCB700-2S+\/42K\u003c\/strong\u003e is a wall-hung, room-sealed gas condensing \u003cstrong\u003eCombi Crossover boiler\u003c\/strong\u003e rated at 42kW DHW output — engineered to deliver hot water to \u003cstrong\u003etwo to three bathrooms simultaneously\u003c\/strong\u003e without the flow or temperature drop-off typical of a conventional combi. Navien's \u003cstrong\u003eON technology\u003c\/strong\u003e maximises recirculation of domestic hot water around the property's pipework, combining the constant, on-demand flow of a system boiler with the space-saving convenience of a combi — removing the need for a hot water cylinder even in larger homes.\u003c\/p\u003e\n\n  \u003cdiv style=\"display:flex; flex-wrap:wrap; gap:12px; margin:0 0 20px 0;\"\u003e\n    \u003cdiv style=\"flex:1; min-width:130px; background-color:#f2f9f8; border-top:3px solid #008377CF; border-radius:6px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:22px; font-weight:700; color:#008377CF;\"\u003e42kW\u003c\/div\u003e\n      \u003cdiv style=\"font-size:13px; color:#555;\"\u003eDHW Output\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:130px; background-color:#f2f9f8; border-top:3px solid #008377CF; border-radius:6px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:22px; font-weight:700; color:#008377CF;\"\u003e94%\u003c\/div\u003e\n      \u003cdiv style=\"font-size:13px; color:#555;\"\u003eErP Efficiency (A)\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:130px; background-color:#f2f9f8; border-top:3px solid #008377CF; border-radius:6px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:22px; font-weight:700; color:#008377CF;\"\u003e17.2 l\/min\u003c\/div\u003e\n      \u003cdiv style=\"font-size:13px; color:#555;\"\u003eDHW Flow (ΔT35°C)\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:130px; background-color:#f2f9f8; border-top:3px solid #008377CF; border-radius:6px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:22px; font-weight:700; color:#008377CF;\"\u003e12:1\u003c\/div\u003e\n      \u003cdiv style=\"font-size:13px; color:#555;\"\u003eTurndown Ratio\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:130px; background-color:#f2f9f8; border-top:3px solid #008377CF; border-radius:6px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:22px; font-weight:700; color:#008377CF;\"\u003e12 yrs\u003c\/div\u003e\n      \u003cdiv style=\"font-size:13px; color:#555;\"\u003eParts \u0026amp; Labour Warranty\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:130px; background-color:#f2f9f8; border-top:3px solid #008377CF; border-radius:6px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:22px; font-weight:700; color:#008377CF;\"\u003e43kg\u003c\/div\u003e\n      \u003cdiv style=\"font-size:13px; color:#555;\"\u003eLift Weight\u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"background-color:#fdecec; border-left:4px solid #c0392b; border-radius:4px; padding:14px 16px; margin:0 0 16px 0;\"\u003e\n    \u003cdiv style=\"font-weight:700; color:#c0392b; margin-bottom:4px;\"\u003eGas Safe Registration Required\u003c\/div\u003e\n    \u003cdiv style=\"color:#444;\"\u003eInstallation, commissioning and servicing of this boiler must be carried out by a \u003cstrong\u003eGas Safe registered engineer\u003c\/strong\u003e. A Benchmark commissioning checklist must be completed and left with the end user, and the flue must be positioned in accordance with the clearances set out in the manufacturer's installation and operation manual.\u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"background-color:#fff6e6; border-left:4px solid #e0a800; border-radius:4px; padding:14px 16px; margin:0 0 24px 0;\"\u003e\n    \u003cdiv style=\"font-weight:700; color:#8a6100; margin-bottom:4px;\"\u003eLPG Conversion \u0026amp; Sizing\u003c\/div\u003e\n    \u003cdiv style=\"color:#444;\"\u003eThe boiler is shipped ready to fire on natural gas, with an \u003cstrong\u003eLPG conversion kit included\u003c\/strong\u003e in the packaging for field conversion by a suitably qualified Gas Safe engineer. Confirm mains water flow rate and pressure are sufficient to make full use of its 17.2 l\/min hot water delivery before ordering.\u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"font-weight:700; font-size:20px; color:#1a1a1a; margin:0 0 14px 0;\"\u003eWhy This Boiler\u003c\/div\u003e\n\n  \u003cdiv style=\"display:flex; flex-wrap:wrap; gap:14px; margin:0 0 28px 0;\"\u003e\n\n    \u003cdiv style=\"flex:1; min-width:260px; background-color:#fff; border:1px solid #e0e0e0; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377CF; margin-bottom:6px;\"\u003eNavien ON Recirculation Technology\u003c\/div\u003e\n      \u003cdiv style=\"color:#444;\"\u003eBuilt-in \u003cstrong\u003eDHW recirculation\u003c\/strong\u003e keeps hot water primed at outlets around the property, removing the wait and the fluctuation between hot and cold that affects conventional combi boilers under heavy simultaneous demand.\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"flex:1; min-width:260px; background-color:#fff; border:1px solid #e0e0e0; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377CF; margin-bottom:6px;\"\u003eASME-Certified Stainless Steel Heat Exchangers\u003c\/div\u003e\n      \u003cdiv style=\"color:#444;\"\u003eDual \u003cstrong\u003eASME-certified stainless steel heat exchangers\u003c\/strong\u003e deliver optimum durability and long-term efficiency, resisting the corrosion that shortens the life of standard combi heat exchangers.\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"flex:1; min-width:260px; background-color:#fff; border:1px solid #e0e0e0; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377CF; margin-bottom:6px;\"\u003eIndustry-Leading 12:1 Turndown\u003c\/div\u003e\n      \u003cdiv style=\"color:#444;\"\u003eA \u003cstrong\u003e12:1 modulation ratio\u003c\/strong\u003e allows the burner to idle at a very low minimum output, improving part-load efficiency and comfort across a wide range of demand.\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"flex:1; min-width:260px; background-color:#fff; border:1px solid #e0e0e0; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377CF; margin-bottom:6px;\"\u003eNaviCirc™ Hot Water Return\u003c\/div\u003e\n      \u003cdiv style=\"color:#444;\"\u003e\n\u003cstrong\u003eNaviCirc™\u003c\/strong\u003e simplifies the setup of a hot water return system using existing pipework, supporting fast, consistent delivery to outlets throughout the property via the boiler's built-in recirculation pump.\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"flex:1; min-width:260px; background-color:#fff; border:1px solid #e0e0e0; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377CF; margin-bottom:6px;\"\u003eHydrogen-Ready (20% Blend)\u003c\/div\u003e\n      \u003cdiv style=\"color:#444;\"\u003eTested and approved for use with up to a \u003cstrong\u003e20% hydrogen blend\u003c\/strong\u003e in the gas supply, helping future-proof the installation against the UK's net zero transition.\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"flex:1; min-width:260px; background-color:#fff; border:1px solid #e0e0e0; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377CF; margin-bottom:6px;\"\u003e12-Year Warranty\u003c\/div\u003e\n      \u003cdiv style=\"color:#444;\"\u003eNavien back the NCB700 ON with a \u003cstrong\u003e12-year parts and labour warranty\u003c\/strong\u003e as standard — the longest in the current Navien gas range.\u003c\/div\u003e\n    \u003c\/div\u003e\n\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"font-weight:700; font-size:20px; color:#1a1a1a; margin:0 0 14px 0;\"\u003eTechnical Specification\u003c\/div\u003e\n\n  \u003cdiv style=\"border:1px solid #e0e0e0; border-radius:6px; overflow:hidden; margin:0 0 28px 0;\"\u003e\n\n    \u003cdiv style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:10px 14px;\"\u003eGeneral\u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eArticle number\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003ePNCB7000042L001 (NCB700-2S+\/42K)\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eBoiler type\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003eWall-hung, room-sealed, fan-assisted condensing \u003cstrong\u003eCombi Crossover\u003c\/strong\u003e\n\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eFuel type\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003eNatural gas (LPG conversion kit included, field conversion required)\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eDimensions (W x D x H)\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e440 x 335 x 695 mm\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eGuarantee\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e\n\u003cstrong\u003e12 years\u003c\/strong\u003e parts and labour\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eShower rating\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003eTwo to three showers\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:10px 14px;\"\u003eHeating Performance\u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eHeat output range (80\/60°C)\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e3.4 – 34.0 kW\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eModulation (max\/min)\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e\u003cstrong\u003e12:1\u003c\/strong\u003e\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:10px 14px;\"\u003eDomestic Hot Water\u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eDHW output range\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e3.5 – 42.0 kW\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eDHW flow rate (ΔT = 25°C)\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e24.1 l\/min\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eDHW flow rate (ΔT = 35°C)\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e17.2 l\/min\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eDHW flow rate, kitchen tap (ΔT = 45°C)\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e13.4 l\/min\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:10px 14px;\"\u003ePerformance \u0026amp; Emissions\u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eErP efficiency\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e\n\u003cstrong\u003eA (94%)\u003c\/strong\u003e — A+ (98%) with single Smart Plus control\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eNOx classification\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003eClass 6\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eLift weight\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e43 kg\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:10px 14px;\"\u003eFlue\u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eFlue diameter\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003eCoaxial 60\/100mm\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#f7f7f7;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eMax. horizontal coaxial flue length\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e20 m\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"display:flex; padding:10px 14px; background-color:#fff;\"\u003e\n      \u003cdiv style=\"flex:1; color:#555;\"\u003eMax. vertical coaxial flue length\u003c\/div\u003e\n      \u003cdiv style=\"flex:1; color:#1a1a1a;\"\u003e21 m\u003c\/div\u003e\n    \u003c\/div\u003e\n\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"font-weight:700; font-size:20px; color:#1a1a1a; margin:0 0 14px 0;\"\u003eFrequently Asked Questions\u003c\/div\u003e\n\n  \u003cdetails style=\"border:1px solid #e0e0e0; border-radius:6px; margin-bottom:8px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:12px 16px; cursor:pointer; list-style:none;\"\u003eWhat does ON technology actually do?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; background-color:#fff; color:#444;\"\u003eIt maximises recirculation of domestic hot water around the property's pipework, so hot water is already primed at outlets rather than needing to travel the full length of pipe from the boiler on every draw-off — reducing water wastage and the wait for hot water.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #e0e0e0; border-radius:6px; margin-bottom:8px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:12px 16px; cursor:pointer; list-style:none;\"\u003eCan this 42kW model really run two or three bathrooms?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; background-color:#fff; color:#444;\"\u003eYes — the NCB700 ON range was designed specifically for large-property hot water demand. The 42kW model delivers 17.2 l\/min at a 35°C temperature rise, comfortably covering two bathrooms with strong simultaneous performance; for guaranteed three-bathroom, high-flow demand the larger 54kW NCB700-3S\/54K model is available.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #e0e0e0; border-radius:6px; margin-bottom:8px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:12px 16px; cursor:pointer; list-style:none;\"\u003eDo I still need a hot water cylinder with this boiler?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; background-color:#fff; color:#444;\"\u003eNo. As a Combi Crossover model, the NCB700 ON supplies domestic hot water directly, without needing a separate storage cylinder, despite its system-boiler-level performance.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #e0e0e0; border-radius:6px; margin-bottom:8px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:12px 16px; cursor:pointer; list-style:none;\"\u003eCan I run this boiler on LPG?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; background-color:#fff; color:#444;\"\u003eAn LPG conversion kit is included in the boiler's packaging as standard, but the boiler ships configured for natural gas. Conversion must be carried out by a Gas Safe registered engineer holding the appropriate LPG qualification.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #e0e0e0; border-radius:6px; margin-bottom:8px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background-color:#008377CF; color:#fff; font-weight:700; padding:12px 16px; cursor:pointer; list-style:none;\"\u003eCan I install this boiler myself?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; background-color:#fff; color:#444;\"\u003eNo. UK law requires that all gas boiler installation, commissioning and servicing work is carried out by a Gas Safe registered engineer.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n\u003c\/div\u003e","brand":"Navien","offers":[{"title":"Default Title","offer_id":66023386349917,"sku":"PNCB7000042L001","price":1895.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0958\/2051\/3629\/files\/NavienCombiBoilerSide.jpg?v=1783090844","url":"https:\/\/qualityheating.co.uk\/products\/navien-ncb700-on-42kw-combi-boiler-pncb7000042l001-12-year-warranty","provider":"AIZO Quality Heating","version":"1.0","type":"link"}