{"product_id":"oso-accu-a100-100l-stainless-steel-buffer-tank-for-heat-pumps","title":"OSO ACCU A100 100L Stainless Steel Buffer Tank for Heat Pumps","description":"\u003cstyle\u003e\n  .oso-buf-wrap{font-family:inherit;color:inherit;line-height:1.7;font-size:16px}\n  .oso-buf-wrap p,.oso-buf-wrap li,.oso-buf-wrap td,.oso-buf-wrap th{font-size:16px!important;line-height:1.7}\n  .oso-buf-wrap h2{font-size:22px!important;font-weight:700;color:#1a3a5c;border-bottom:3px solid #0077b6;padding-bottom:6px;margin:2rem 0 1rem;line-height:1.3}\n  .oso-buf-wrap p{margin:0 0 1rem}\n  .oso-buf-wrap ul{padding-left:1.5rem;margin:0 0 1rem}\n  .oso-buf-wrap ul li{margin-bottom:0.5rem}\n  .oso-buf-badge{display:inline-block;font-size:13px!important;font-weight:700;border-radius:4px;padding:2px 10px;margin-right:5px;margin-bottom:4px;vertical-align:middle}\n  .oso-buf-badge.blue{background:#0077b6;color:#fff}\n  .oso-buf-badge.navy{background:#1a3a5c;color:#fff}\n  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.oso-buf-why-box{background:#fff3cd;border:1px solid #ffc107;border-radius:5px;padding:0.9rem 1.1rem;margin:0.8rem 0 1.2rem}\n  .oso-buf-spec-table{width:100%;border-collapse:collapse;margin-bottom:1.5rem}\n  .oso-buf-spec-table th{background:#1a3a5c;color:#fff!important;text-align:left;padding:0.7rem 1rem;font-weight:700;font-size:16px!important}\n  .oso-buf-spec-table td{padding:0.6rem 1rem;border-bottom:1px solid #bde0f5;vertical-align:top;font-size:16px!important}\n  .oso-buf-spec-table tr:nth-child(even) td{background:#e0f2fe}\n  .oso-buf-spec-table td:first-child{font-weight:600;color:#111;width:44%}\n  .oso-buf-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:0.85rem;margin-bottom:1.2rem}\n  .oso-buf-card{background:#e0f2fe;border:1px solid #90caf9;border-radius:6px;padding:1rem 1.1rem;line-height:1.6}\n  .oso-buf-card strong{display:block;color:#1a3a5c;margin-bottom:0.35rem;font-size:16px!important}\n  .oso-buf-faq-item{border-bottom:1px solid #bde0f5;padding:0.9rem 0}\n  .oso-buf-faq-item:last-child{border-bottom:none}\n  .oso-buf-faq-item strong{color:#1a3a5c;font-size:16px!important;display:block;margin-bottom:0.3rem}\n\u003c\/style\u003e\n\u003cdiv class=\"oso-buf-wrap\"\u003e\n\n  \u003cdiv style=\"margin-bottom:1rem\"\u003e\n    \u003cspan class=\"oso-buf-badge blue\"\u003eOSO ACCU A100\u003c\/span\u003e\n    \u003cspan class=\"oso-buf-badge navy\"\u003e100 Litres\u003c\/span\u003e\n    \u003cspan class=\"oso-buf-badge green\"\u003eStainless Steel\u003c\/span\u003e\n    \u003cspan class=\"oso-buf-badge grey\"\u003eNANOPUR Insulation\u003c\/span\u003e\n    \u003cspan class=\"oso-buf-badge grey\"\u003eSKU 11003162\u003c\/span\u003e\n    \u003cspan class=\"oso-buf-badge grey\"\u003eErP B\u003c\/span\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"oso-buf-feature-strip\"\u003e\n    \u003cdiv class=\"oso-buf-feat\"\u003e\n\u003cdiv class=\"feat-icon\"\u003e🏗️\u003c\/div\u003e\n\u003cdiv class=\"feat-label\"\u003eStainless Steel\u003c\/div\u003e\n\u003cdiv class=\"feat-value\"\u003eEVERLAST™ titanium alloy\u003c\/div\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-feat\"\u003e\n\u003cdiv class=\"feat-icon\"\u003e🌡️\u003c\/div\u003e\n\u003cdiv class=\"feat-label\"\u003eNANOPUR Insulation\u003c\/div\u003e\n\u003cdiv class=\"feat-value\"\u003eClass-leading retention\u003c\/div\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-feat\"\u003e\n\u003cdiv class=\"feat-icon\"\u003e🔄\u003c\/div\u003e\n\u003cdiv class=\"feat-label\"\u003eDual Connections\u003c\/div\u003e\n\u003cdiv class=\"feat-value\"\u003eFlow + return both sides\u003c\/div\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-feat\"\u003e\n\u003cdiv class=\"feat-icon\"\u003e🛡️\u003c\/div\u003e\n\u003cdiv class=\"feat-label\"\u003eAnti-Clocking\u003c\/div\u003e\n\u003cdiv class=\"feat-value\"\u003eProtects heat pump\u003c\/div\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-feat\"\u003e\n\u003cdiv class=\"feat-icon\"\u003e📏\u003c\/div\u003e\n\u003cdiv class=\"feat-label\"\u003e100L Mid-Range\u003c\/div\u003e\n\u003cdiv class=\"feat-value\"\u003eØ434 × 1,168mm\u003c\/div\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-feat\"\u003e\n\u003cdiv class=\"feat-icon\"\u003e🔩\u003c\/div\u003e\n\u003cdiv class=\"feat-label\"\u003eWall Brackets\u003c\/div\u003e\n\u003cdiv class=\"feat-value\"\u003eIncluded\u003c\/div\u003e\n\u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"oso-buf-intro-box\"\u003e\n    \u003cp\u003e\u003cstrong\u003eOSO ACCU A100 — 100L Stainless Steel Buffer Tank for Heat Pumps (SKU 11003162)\u003c\/strong\u003e — 100L stainless steel buffer tank  |  NANOPUR insulation  |  ErP B  |  Dual flow\/return connections  |  Hydraulic coupling \u0026amp; balancing  |  Anti-clocking protection  |  Cool storage function  |  G½\" air vent + drain  |  Wall brackets included  |  Ø434 × 1,168mm  |  28 kg\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"oso-buf-why-box\"\u003e\n    \u003cstrong style=\"color:#856404\"\u003eℹ️ Why does my heat pump need a buffer tank?\u003c\/strong\u003e\n    \u003cp style=\"margin:0.3rem 0 0;color:#5a3a00\"\u003eMost air source heat pumps require a minimum flow rate to operate correctly. Without sufficient water volume, the pump can \"clock\" (short-cycle), reducing efficiency and increasing compressor wear. A buffer tank adds volume so the heat pump runs in longer, more efficient cycles. The buffer also provides the thermal mass for defrost cycles and, in heating-cooling systems, stores cooled water during summer operation. The 100L A100 suits heat pumps from approximately 5–12kW output in typical domestic systems.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cp\u003eThe \u003cstrong\u003eOSO ACCU A100\u003c\/strong\u003e is the mid-range 100-litre model in the OSO ACCU stainless steel buffer tank series. It shares the same Ø434mm diameter column as the A60, making it a natural upgrade when a system assessment calls for more volume — for instance, where the heat pump output is higher, where fewer heating zones reduce average flow rates, or where the installer wants additional thermal mass for improved defrost performance.\u003c\/p\u003e\n  \u003cp\u003eConstructed from EVERLAST™ titanium-alloyed stainless steel with ULTRAWELD™ manufacturing and NANOPUR™ insulation, the A100 is inherently corrosion-free and requires no magnesium anode, no periodic recoating and no anti-freeze. Its ErP B energy rating confirms low standby losses (55W), ensuring the stored system volume stays at temperature with minimal energy input between heat pump cycles.\u003c\/p\u003e\n\n  \u003ch2\u003eKey Features\u003c\/h2\u003e\n  \u003cdiv class=\"oso-buf-grid\"\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eHydraulic Coupling \u0026amp; Balancing\u003c\/strong\u003eDecouples the heat pump primary circuit from the heating distribution circuit, allowing the heat pump to maintain its required minimum flow rate independently of variable demand from individual heating zones.\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eAnti-Clocking Protection\u003c\/strong\u003e100L of additional system volume prevents the heat pump from short-cycling — keeping compressor run times long, COP consistently high and wear to a minimum.\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eDefrost Heat Reserve\u003c\/strong\u003eProvides sufficient thermal mass for the heat pump to complete a full defrost cycle without drawing energy away from the heating circuit — critical for reliable cold-climate performance.\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eCool Storage for Heating-Cooling Systems\u003c\/strong\u003eStores cooled water during summer cooling mode so the heat pump can simultaneously heat a DHW cylinder without the two functions conflicting on the refrigeration circuit.\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eNANOPUR™ Insulation · ErP B\u003c\/strong\u003eClass-leading insulation maintains stored water temperature with standby losses of just 55W. ErP B rating confirms compliance with current energy efficiency regulations for buffer vessels.\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eEVERLAST™ Stainless Steel · ULTRAWELD™\u003c\/strong\u003eTitanium-alloyed stainless steel with OSO's unique ULTRAWELD welding process and passivation — no enamel lining, no sacrificial anode, inherently corrosion-resistant. Over 40% lighter than enamelled alternatives.\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eDual Flow\/Return Connections\u003c\/strong\u003eTwo complete sets of flow and return connections on opposite sides provide flexible primary\/secondary piping options to suit various system layouts.\u003c\/div\u003e\n    \u003cdiv class=\"oso-buf-card\"\u003e\n\u003cstrong\u003eWall Brackets \u0026amp; Drain Included\u003c\/strong\u003eCorrosion-resistant wall brackets for wall-mounted installation supplied. G½\" F air vent connection and drain point factory-fitted. Sensor pocket for a 6–8mm probe included.\u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n  \u003ctable class=\"oso-buf-spec-table\"\u003e\n    \u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eDetail\u003c\/th\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eBrand \/ Range\u003c\/td\u003e\n\u003ctd\u003eOSO Hotwater \/ ACCU\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003eACCU A100\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSKU \/ Product No.\u003c\/td\u003e\n\u003ctd\u003e11003162\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eVolume\u003c\/td\u003e\n\u003ctd\u003e100 litres\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eEnergy Rating (ErP)\u003c\/td\u003e\n\u003ctd\u003eB\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eStandby Heat Loss\u003c\/td\u003e\n\u003ctd\u003e55W\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eTank Material\u003c\/td\u003e\n\u003ctd\u003eEVERLAST™ titanium-alloyed stainless steel\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eConstruction\u003c\/td\u003e\n\u003ctd\u003eULTRAWELD™ — no enamel, no anode required\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eInsulation\u003c\/td\u003e\n\u003ctd\u003eNANOPUR™\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDiameter (Ø)\u003c\/td\u003e\n\u003ctd\u003e434mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHeight (H)\u003c\/td\u003e\n\u003ctd\u003e1,168mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eWeight (empty)\u003c\/td\u003e\n\u003ctd\u003e28 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFreight Volume\u003c\/td\u003e\n\u003ctd\u003e0.27 dm³\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePlacement\u003c\/td\u003e\n\u003ctd\u003eFloor-standing (wall-mountable with included brackets)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFlow\/Return Connections\u003c\/td\u003e\n\u003ctd\u003eDual sets — flexible configuration\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eAir Vent Connection\u003c\/td\u003e\n\u003ctd\u003eG½\" F (separate)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDrain Connection\u003c\/td\u003e\n\u003ctd\u003eYes — factory fitted\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSensor Pocket\u003c\/td\u003e\n\u003ctd\u003e1× for 6–8mm sensor\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eWall Brackets\u003c\/td\u003e\n\u003ctd\u003eIncluded (corrosion-resistant)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eTypical Applications\u003c\/td\u003e\n\u003ctd\u003eAir source heat pumps 5–12kW, solar thermal, heating-cooling systems\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/table\u003e\n\n  \u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n  \u003cdiv class=\"oso-buf-faq-item\"\u003e\n\u003cstrong\u003eWhen would I choose the 100L over the 60L buffer tank?\u003c\/strong\u003e\u003cp\u003eThe 100L A100 is appropriate where the heat pump output is higher (typically 7kW+), where the distribution system has fewer zones and therefore a higher risk of low flow rates during part-load operation, or where the installer wants additional thermal mass for more reliable defrost performance in cold climates. As a rough guide, 20–50L per kW of heat pump output is a common sizing approach — for an 8kW heat pump, 100L sits comfortably in range. Always refer to the heat pump manufacturer's minimum buffer volume specification and any MCS system sizing guidance.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"oso-buf-faq-item\"\u003e\n\u003cstrong\u003eDoes the A100 need an inhibitor or anti-freeze?\u003c\/strong\u003e\u003cp\u003eNo inhibitor or anti-freeze is required by the tank itself — the stainless steel construction is inherently corrosion-resistant. However, your heat pump's primary circuit may require a suitable inhibitor or glycol mixture per the heat pump manufacturer's instructions. Always follow the heat pump manufacturer's guidance on system water treatment.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"oso-buf-faq-item\"\u003e\n\u003cstrong\u003eCan this buffer tank be used with a ground source heat pump?\u003c\/strong\u003e\u003cp\u003eYes. The OSO ACCU A100 is compatible with any closed heating circuit — air source, ground source, solar thermal or hybrid systems. Its dual connections and neutral stainless steel construction make it suitable for use with all common system inhibitors and glycol concentrations.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"oso-buf-faq-item\"\u003e\n\u003cstrong\u003eDoes a buffer tank need servicing?\u003c\/strong\u003e\u003cp\u003eThe OSO ACCU stainless steel buffer tanks require minimal maintenance — there is no anode to replace, no enamel to inspect and no re-pressurisation of linings. Annual visual inspection of connections, the drain, and the air vent for leaks or corrosion is recommended as part of an annual heat pump service. System inhibitor concentrations should be checked annually per the heat pump manufacturer's schedule.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"OSO Hotwater","offers":[{"title":"Default Title","offer_id":63667187351901,"sku":"ACCU A100","price":590.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0958\/2051\/3629\/files\/OSOACCUA100StainlessSteelBufferTankforHeatPumps.webp?v=1772363049","url":"https:\/\/qualityheating.co.uk\/products\/oso-accu-a100-100l-stainless-steel-buffer-tank-for-heat-pumps","provider":"AIZO Quality Heating","version":"1.0","type":"link"}