{"product_id":"ariston-nuos-plus-s2-wi-fi-250l-heat-pump-water-heater-unvented-kit","title":"Ariston Nuos Plus S2 Wi-Fi 250L Heat Pump Water Heater + Unvented Kit","description":"\u003cdiv style=\"font-size:16px; font-family:Georgia,'Times New Roman',serif; color:#1a1a1a; max-width:900px; margin:0 auto; padding:0 16px;\"\u003e\n\n  \u003cp style=\"font-size:17px; line-height:1.75; margin:0 0 20px;\"\u003e\n    The \u003cstrong\u003eAriston Nuos Plus S2 Wi-Fi 250I\u003c\/strong\u003e is Ariston's flagship \u003cstrong\u003efloor-standing air source heat pump water heater\u003c\/strong\u003e — an indirect, 245-litre model that pairs an ultra-efficient \u003cstrong\u003eR290 (propane) heat pump\u003c\/strong\u003e with an integrated \u003cstrong\u003e0.65 m² secondary heat-exchange coil\u003c\/strong\u003e for seamless connection to a solar thermal system, boiler, or other primary heat generator. Supplied with a \u003cstrong\u003eG3 unvented safety kit\u003c\/strong\u003e, the 250I achieves a class-leading \u003cstrong\u003eCOP of 3.51\u003c\/strong\u003e at 7 °C ambient air (EN 16147) and earns an \u003cstrong\u003eErP A+ energy rating\u003c\/strong\u003e (tapping profile XL) — making it the ideal choice for larger households, self-builders, and any property already investing in solar thermal or hybrid heating.\n  \u003c\/p\u003e\n\n  \u003cdiv style=\"display:flex; flex-wrap:wrap; gap:12px; margin:0 0 28px;\"\u003e\n    \u003cdiv style=\"flex:1 1 130px; background:#008377CF; color:#fff; border-radius:8px; padding:16px 14px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:28px; font-weight:700; line-height:1;\"\u003e3.51\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px; opacity:.9;\"\u003eCOP @ 7 °C air\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1 1 130px; background:#008377CF; color:#fff; border-radius:8px; padding:16px 14px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:28px; font-weight:700; line-height:1;\"\u003eA+\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px; opacity:.9;\"\u003eErP Energy Rating\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1 1 130px; background:#008377CF; color:#fff; border-radius:8px; padding:16px 14px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:28px; font-weight:700; line-height:1;\"\u003e245 L\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px; opacity:.9;\"\u003eTank Capacity\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1 1 130px; background:#008377CF; color:#fff; border-radius:8px; padding:16px 14px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:28px; font-weight:700; line-height:1;\"\u003e48 dB\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px; opacity:.9;\"\u003eIndoor Sound Level\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1 1 130px; background:#008377CF; color:#fff; border-radius:8px; padding:16px 14px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:28px; font-weight:700; line-height:1;\"\u003eR290\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px; opacity:.9;\"\u003eGWP = 3 Refrigerant\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1 1 130px; background:#008377CF; color:#fff; border-radius:8px; padding:16px 14px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:28px; font-weight:700; line-height:1;\"\u003e1,162\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px; opacity:.9;\"\u003ekWh\/year (avg climate)\u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"border-left:4px solid #c0392b; background:#fdf3f2; border-radius:0 6px 6px 0; padding:13px 16px; margin:0 0 14px;\"\u003e\n    \u003cstrong style=\"color:#c0392b;\"\u003e⚠ Installer Note — R290 Flammable Refrigerant:\u003c\/strong\u003e R290 is a class A3 flammable refrigerant. Installation and commissioning \u003cstrong\u003emust be undertaken by a suitably competent engineer\u003c\/strong\u003e trained in safe working with flammable refrigerant systems (BS EN 378, IEC 60335-2-40 Annex CC). The installation room must have a \u003cstrong\u003eminimum volume of 20 m³\u003c\/strong\u003e with adequate ventilation and must not contain any open-flued combustion appliance.\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"border-left:4px solid #e67e22; background:#fef9f0; border-radius:0 6px 6px 0; padding:13px 16px; margin:0 0 14px;\"\u003e\n    \u003cstrong style=\"color:#e67e22;\"\u003e⚡ Unvented System — G3 Competency Required:\u003c\/strong\u003e Supplied with an unvented kit and classed as a G3 unvented hot water storage system. Installation \u003cstrong\u003emust be performed by an approved installer holding a current G3 qualification\u003c\/strong\u003e, notified to Building Control under Part G of the Building Regulations. All discharge pipework must be installed to BS 8558.\n  \u003c\/div\u003e\n\n  \u003cdiv style=\"border-left:4px solid #008377CF; background:#e6f4f3; border-radius:0 6px 6px 0; padding:13px 16px; margin:0 0 28px;\"\u003e\n    \u003cstrong style=\"color:#005c54;\"\u003eⓘ 250I — Indirect Model with Secondary Coil:\u003c\/strong\u003e The 250I is fitted with a \u003cstrong\u003e0.65 m² stainless steel heat-exchange coil\u003c\/strong\u003e in the lower cylinder section, allowing a \u003cstrong\u003esolar thermal collector, oil or gas boiler, or other compatible heat generator\u003c\/strong\u003e to supply heat via a closed primary circuit (max 15 L\/min, max 6 bar). The heat pump and 1800 W backup element remain available as supplementary sources at all times. For a direct cylinder without a coil, see the \u003cstrong\u003e200D (MPN 4057138)\u003c\/strong\u003e.\n  \u003c\/div\u003e\n\n  \u003ch3 style=\"font-size:17px; font-weight:700; color:#005c54; border-bottom:2px solid #008377CF; padding-bottom:6px; margin:0 0 18px;\"\u003eKey Features\u003c\/h3\u003e\n  \u003cdiv style=\"display:grid; grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); gap:14px; margin:0 0 32px;\"\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eNear-Zero Carbon Refrigerant\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eUses \u003cstrong\u003eR290 natural refrigerant\u003c\/strong\u003e with a GWP of just 3 — over 470 times lower than the R134a used in the previous Nuos generation. The factory-sealed, pre-charged circuit means \u003cstrong\u003eno on-site refrigerant handling\u003c\/strong\u003e and near-zero direct emissions over the product's lifetime, fully aligned with current and forthcoming F-Gas legislation.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eClass-Leading COP of 3.51\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eAt the EN 16147 standard test condition (7 °C air \/ 10 °C cold inlet \/ 55 °C set-point), the 250I achieves a \u003cstrong\u003eCOP of 3.51\u003c\/strong\u003e — every unit of electricity delivers over 3.5 units of useful heat. Against the XL tapping profile, annual electricity consumption averages just \u003cstrong\u003e1,161.5 kWh\/year\u003c\/strong\u003e under average climatic conditions.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eIndirect Coil — Multi-Source Heating\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eThe \u003cstrong\u003e0.65 m² lower heat-exchange coil\u003c\/strong\u003e accepts heat from a solar thermal array, gas or oil boiler, or solid fuel back-boiler. At 15 L\/min primary flow, the coil delivers up to \u003cstrong\u003e9.76 kW\u003c\/strong\u003e — heating the full cylinder from 15 °C to 60 °C in under 59 minutes — enabling a true \u003cstrong\u003esolar-plus-heat-pump hybrid system\u003c\/strong\u003e for maximum efficiency.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eBuilt-in Wi-Fi and Ariston Net App\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003e\u003cstrong\u003eIntegrated Wi-Fi gateway\u003c\/strong\u003e links to the \u003cstrong\u003eAriston Net app\u003c\/strong\u003e (iOS and Android) out of the box — no dongle or bridge required. Control temperature, set schedules, monitor energy consumption, activate Away mode, and receive system alerts remotely. \u003cstrong\u003eOptional voice control\u003c\/strong\u003e via compatible smart-home platforms is supported.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eIntegrated Solar PV Function\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eBuilt-in \u003cstrong\u003eSG1\/SG2 Smart Grid signal inputs\u003c\/strong\u003e detect surplus solar generation and automatically switch the unit to a higher-output heating mode — maximising PV self-consumption without a separate diverter device. The PV boost temperature is fully configurable by the installer via the PV SET parameter.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eUltra-Quiet — 48 dB(A)\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eThe S2 generation operates at just \u003cstrong\u003e48 dB(A)\u003c\/strong\u003e (EN 12102-2, ducted Ø200) — measurably quieter than its predecessor. An optional \u003cstrong\u003eNight function\u003c\/strong\u003e drops fan speed further for whisper-quiet overnight operation, making the unit suitable for installations in or adjacent to habitable rooms.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eAdvanced Modes inc. i-Memory\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eIncludes \u003cstrong\u003eGreen\u003c\/strong\u003e, \u003cstrong\u003eGreen+\u003c\/strong\u003e, \u003cstrong\u003eBoost\u003c\/strong\u003e, \u003cstrong\u003eComfort\u003c\/strong\u003e, \u003cstrong\u003ei-Memory\u003c\/strong\u003e (learns four weeks of demand patterns and schedules accordingly), daily and weekly \u003cstrong\u003eprogramme schedules\u003c\/strong\u003e, \u003cstrong\u003eAnti-Legionella\u003c\/strong\u003e automatic thermal sanitisation, and \u003cstrong\u003eVoyage\u003c\/strong\u003e (holiday away mode with timed reactivation) — all accessible from the touch display or the app.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eTitanshield Dual-Protection Tank\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eThe 245-litre steel cylinder is protected by \u003cstrong\u003eTitanshield anti-corrosion enamel\u003c\/strong\u003e and a \u003cstrong\u003ereplaceable sacrificial magnesium anode\u003c\/strong\u003e accessible via a dedicated service flange without draining the tank. Outer insulation is 50 mm polyurethane — CFC and HCFC free — covered in a galvanised pre-painted steel jacket.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eWide Operating Range: -10 C to +42 C\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eA \u003cstrong\u003ehot-gas defrost valve\u003c\/strong\u003e allows uninterrupted heat pump operation down to \u003cstrong\u003e-10 C ambient\u003c\/strong\u003e by preventing condenser condensate from freezing — extending the hours each year the compressor runs rather than the element. At higher ambients (up to +42 C) efficiency improves further, reducing running costs in warmer seasons.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eBusBridgeNet System Integration\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eEquipped with \u003cstrong\u003eAriston BusBridgeNet\u003c\/strong\u003e connectivity. Connects to a Sensys HD remote control and other BusBridgeNet-compatible Ariston products — boilers, heating heat pumps, solar controllers — on a shared bus. A single Ariston Net Wi-Fi gateway on the bus manages \u003cstrong\u003eheating and domestic hot water from one app\u003c\/strong\u003e across the whole system.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eComplete G3 Unvented Kit Included\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eThe MPN 4057139 bundle includes a \u003cstrong\u003ecomplete G3-compliant unvented safety assembly\u003c\/strong\u003e — pressure reducing valve, expansion vessel, TPRV, combination PRV, and tundish — correctly rated for this 245-litre cylinder. This reduces installer procurement time and ensures all safety components are factory-matched to the unit.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"border:1px solid #d4e8e6; border-radius:8px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#005c54; margin-bottom:6px;\"\u003eFlexible 150\/160\/200 mm Ducting\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:15px; line-height:1.6;\"\u003eAccepts \u003cstrong\u003e150, 160, or 200 mm duct\u003c\/strong\u003e on both inlet and exhaust, with \u003cstrong\u003e189 Pa available static pressure\u003c\/strong\u003e for extended duct runs to an external wall or adjacent space. Operates without ducting in rooms of at least 20 m³. Ships lying flat with built-in carry straps for safe internal manoeuvring, and has \u003cstrong\u003eadjustable levelling feet\u003c\/strong\u003e.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n  \u003c\/div\u003e\n\n  \u003ch3 style=\"font-size:17px; font-weight:700; color:#005c54; border-bottom:2px solid #008377CF; padding-bottom:6px; margin:0 0 16px;\"\u003eTechnical Specifications — Nuos Plus S2 Wi-Fi 250I\u003c\/h3\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse; font-size:15px; margin:0 0 32px;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr style=\"background:#008377CF; color:#fff;\"\u003e\n        \u003ctd colspan=\"2\" style=\"padding:10px 12px; font-weight:700; font-size:14px; letter-spacing:.05em;\"\u003eGENERAL\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; width:55%;\"\u003eMPN \/ Product Code\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e4057139\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eModel\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003eNuos Plus S2 Wi-Fi 250I + Unvented Kit\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eTank Configuration\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003eIndirect (with secondary heat-exchange coil)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eRated Tank Capacity\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e245 litres\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eErP Energy Class (DHW)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003eA+ (tapping profile XL)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eAnnual Electricity Consumption (average climate)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e1,161.5 kWh\/year\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eWeight (empty)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e123 kg\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eDimensions (H x W x D)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e1931 x 635 x 653 mm\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eInsulation Thickness\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003eapprox 50 mm polyurethane (CFC\/HCFC-free)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eInternal Tank Protection\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003eTitanshield enamel + sacrificial magnesium anode\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Operating Pressure\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e0.6 MPa (6 bar)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eHydraulic Connections\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e3\/4\" BSP — cold in \/ hot out \/ coil ports (D,E)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#008377CF; color:#fff;\"\u003e\n        \u003ctd colspan=\"2\" style=\"padding:10px 12px; font-weight:700; font-size:14px; letter-spacing:.05em;\"\u003eHEAT PUMP\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eRefrigerant\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003eR290 (propane) — GWP = 3\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eRefrigerant Charge\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e0.15 kg\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eCOP at 7 C air \/ 10 C inlet \/ 55 C set (EN 16147)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e3.51\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eHeating Time (EN 16147, 7 C air)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e8 hr 44 min\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Electrical Power (heat pump)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e600 W\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Water Temperature (heat pump mode)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e65 C\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eAmbient Operating Range\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e-10 C to +42 C\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMixed Water at 40 C (V40, EN 812\/2013)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e339 litres\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eStanding Losses (Pes)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e26 W\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#008377CF; color:#fff;\"\u003e\n        \u003ctd colspan=\"2\" style=\"padding:10px 12px; font-weight:700; font-size:14px; letter-spacing:.05em;\"\u003eSECONDARY COIL (INDIRECT)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eCoil Surface Area\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e0.65 m2\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eCoil Volume\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e0.0047 m3\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Primary Supply Pressure\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e6 bar\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003ePrimary Flow Rate\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e15 L\/min\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eCoil Pressure Drop at 15 L\/min\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e18 mbar\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003ePrimary Heating Power Input\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e9.76 kW\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eCoil Heating Time (15 C to 60 C)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e58 min 40 sec\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Water Temp with External Integration\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e65 C\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eCoil Connection Diameter\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e3\/4\" G BSP\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#008377CF; color:#fff;\"\u003e\n        \u003ctd colspan=\"2\" style=\"padding:10px 12px; font-weight:700; font-size:14px; letter-spacing:.05em;\"\u003eAIR CIRCUIT\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eStandard Air Flow Rate\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e380 m3\/h (auto modulating)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eAvailable Static Pressure\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e189 Pa\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eDuct Diameters Accepted\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e150 mm \/ 160 mm \/ 200 mm\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMinimum Room Volume (unducted)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e20 m3\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eIndoor Sound Power Level\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e48 dB(A) (EN 12102-2, ducted O200)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#008377CF; color:#fff;\"\u003e\n        \u003ctd colspan=\"2\" style=\"padding:10px 12px; font-weight:700; font-size:14px; letter-spacing:.05em;\"\u003eELECTRICAL AND BACKUP ELEMENT\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003ePower Supply\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e220-240 V ~ 50 Hz, single phase\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Total Power Consumption\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e2400 W\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eBackup Heating Element\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e1800 W steatite immersion\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Water Temperature (element mode)\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e65 C (factory set)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr style=\"background:#f5fbfb;\"\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eMax Current Consumption\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003e10.5 A\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6;\"\u003eProtection Rating\u003c\/td\u003e\n        \u003ctd style=\"padding:9px 12px; border-bottom:1px solid #d4e8e6; font-weight:600;\"\u003eIPX4\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3 style=\"font-size:17px; font-weight:700; color:#005c54; border-bottom:2px solid #008377CF; padding-bottom:6px; margin:0 0 16px;\"\u003eFrequently Asked Questions\u003c\/h3\u003e\n\n  \u003cdetails style=\"border:1px solid #d4e8e6; border-radius:8px; margin-bottom:10px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background:#008377CF; color:#fff; padding:13px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eCan the 250I be connected to an existing solar thermal system?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; font-size:15px; line-height:1.7;\"\u003eYes — this is a primary design advantage of the 250I. The lower \u003cstrong\u003e0.65 m² coil\u003c\/strong\u003e accepts heat from a solar thermal array via the \u003cstrong\u003e3\/4\" coil ports (connections D and E)\u003c\/strong\u003e. A dedicated sensor pocket (sheath S2) takes a temperature probe for solar controller integration. Primary flow should not exceed 15 L\/min and primary pressure must not exceed 6 bar. Consult the solar controller manufacturer's installation guide for compatible wiring configurations and system design guidance.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #d4e8e6; border-radius:8px; margin-bottom:10px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background:#008377CF; color:#fff; padding:13px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eDoes installation require F-Gas certification?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; font-size:15px; line-height:1.7;\"\u003eNo F-Gas handling certification is required. The \u003cstrong\u003esealed R290 circuit is factory-charged\u003c\/strong\u003e and not opened on site. However, R290 is a class A3 (highly flammable) refrigerant — installers must be \u003cstrong\u003ecompetent in safe working with flammable refrigerant systems\u003c\/strong\u003e (BS EN 378, IEC 60335-2-40 Annex CC) and must verify the room is free of ignition sources and meets minimum volume and ventilation requirements. A \u003cstrong\u003eG3 qualification remains mandatory\u003c\/strong\u003e for the unvented cylinder installation.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #d4e8e6; border-radius:8px; margin-bottom:10px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background:#008377CF; color:#fff; padding:13px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eHow does the 250I integrate with a gas or oil boiler?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; font-size:15px; line-height:1.7;\"\u003eThe 250I can be configured to call an external boiler as a \u003cstrong\u003esupplementary heat source\u003c\/strong\u003e via the \u003cstrong\u003eAUX output contact\u003c\/strong\u003e (installer parameter P14 = 1). When the heat pump cannot satisfy demand, the unit signals the boiler to provide heat through the secondary coil. For \u003cstrong\u003eBusBridgeNet-compatible Ariston boilers\u003c\/strong\u003e, the connection enables fully coordinated system management through the Sensys HD control or the Ariston Net app — with heating and domestic hot water managed together from a single interface.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #d4e8e6; border-radius:8px; margin-bottom:10px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background:#008377CF; color:#fff; padding:13px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eWhat is the minimum ceiling height required for the 250I?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; font-size:15px; line-height:1.7;\"\u003eThe 250I stands \u003cstrong\u003e1931 mm tall\u003c\/strong\u003e. For unducted operation, ceiling height must be at least \u003cstrong\u003e2200 mm\u003c\/strong\u003e (approximately 270 mm clearance). For ducted installations: \u003cstrong\u003eO150 mm PVC requires at least 2310 mm\u003c\/strong\u003e, \u003cstrong\u003eO160 mm PEHD at least 2400 mm\u003c\/strong\u003e, and \u003cstrong\u003eO200 mm PVC at least 2320 mm\u003c\/strong\u003e. Minimum horizontal clearance is 500 mm on each side for maintenance access. The unit ships horizontally with carry straps for safe internal handling and has adjustable levelling feet for uneven floors.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #d4e8e6; border-radius:8px; margin-bottom:10px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background:#008377CF; color:#fff; padding:13px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eWhat features does the Ariston Net app provide for the 250I?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; font-size:15px; line-height:1.7;\"\u003eThe \u003cstrong\u003eAriston Net app\u003c\/strong\u003e (iOS and Android) connects via the integrated Wi-Fi gateway — no separate dongle needed. Features include: remote temperature adjustment; daily and weekly scheduling; mode switching (Green, Boost, i-Memory, Comfort, etc.); real-time and historical energy monitoring; Away\/Voyage mode with timed reactivation; and push notifications for system alerts. \u003cstrong\u003eOptional voice control\u003c\/strong\u003e via compatible smart-home platforms is supported. Installers with an Ariston professional account can access diagnostic data and receive remote fault alerts.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"border:1px solid #d4e8e6; border-radius:8px; margin-bottom:10px; overflow:hidden;\"\u003e\n    \u003csummary style=\"background:#008377CF; color:#fff; padding:13px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eWhat ongoing maintenance does the 250I require?\u003c\/summary\u003e\n    \u003cdiv style=\"padding:14px 16px; font-size:15px; line-height:1.7;\"\u003eAnnual servicing by a qualified engineer should include: inspection and replacement of the \u003cstrong\u003esacrificial magnesium anode\u003c\/strong\u003e (accessible without draining the tank via the dedicated service flange); \u003cstrong\u003ecleaning of the evaporator filter\u003c\/strong\u003e (front-access without removing duct connections); checking unvented safety components (TPRV, PRV, expansion vessel pre-charge pressure); and a functional check of all operating modes and the app connection. The built-in \u003cstrong\u003eAnti-Legionella thermal sanitisation\u003c\/strong\u003e function can be scheduled to run automatically, maintaining compliance with CIBSE hot water hygiene guidance without manual intervention.\u003c\/div\u003e\n  \u003c\/details\u003e\n\n\u003c\/div\u003e","brand":"Ariston","offers":[{"title":"Default Title","offer_id":64736114245981,"sku":"4057139","price":2595.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0958\/2051\/3629\/files\/AristonNuosPlusS2Wi-FiHeatPumpWaterHeater.webp?v=1779179402","url":"https:\/\/qualityheating.co.uk\/products\/ariston-nuos-plus-s2-wi-fi-250l-heat-pump-water-heater-unvented-kit","provider":"AIZO Quality Heating","version":"1.0","type":"link"}