WaterBoost 450 Litre Horizontal Accumulator Vessel AWBH-450LH

The WaterBoost AWBH-450LH is a 450-litre WRAS-approved horizontal accumulator vessel for mains-connected water systems — the largest in the horizontal range. The horizontal orientation makes it ideal where headroom is limited, fitting on its side in a loft, cupboard or plant room. Accumulators store mains water under pressure so you draw instantly at full mains pressure the moment you open a tap or shower, delivering noticeably stronger, more consistent flow even during peak demand periods. The AWBH-450LH operates on a 60% usable volume ratio — delivering approximately 270 litres of high-pressure water before returning to normal mains flow. At a typical shower flow of 12 l/min, 270L supports two simultaneous showers for approximately 11 minutes, or three showers for approximately 7.5 minutes. Diaphragm design, WRAS-approved construction, maintenance free. Suited to 3 bedroom+ and larger properties with higher simultaneous demand where a vertical vessel won’t fit. Requires a minimum 2 bar static mains pressure to operate effectively. If your static pressure is below 2 bar, add the WaterBoost ACF1 accumulator booster pump to charge the vessel to the required working pressure. ↕ View dimensions & install footprint Vessel length (A) 1822 mm Vessel diameter / height (B) plus feet 662 mm Water stored when full confirm joist/floor loading before a loft install 450 kg + vessel Max working pressure 10 bar Fits through a standard 762 mm doorway. Check any loft hatch against the 662 mm diameter. 450L Vessel size 270L Usable output 10bar Max pressure WRAS Approved WRAS approved Horizontal — low headroom Largest horizontal model Maintenance free No pump — no power 3 bedroom+ homes ACF1 pump if <2 bar