WaterBoost ATX-300H – 3.0 bar Horizontal Whole-House Mains Pressure Booster

The WaterBoost ATX-300H is the largest horizontal model in the ATX integrated accumulator booster range, built for lofts, eaves, under-bath voids and low cupboards. It connects directly to the incoming cold water mains, combining a 300-litre sealed horizontal accumulator vessel with a variable speed pump mounted beside or in front of it — automatically boosting both pressure and flow throughout the property the moment a tap or shower is opened. No break tank, no overflow arrangement, just two water connections required.

The system delivers a peak burst flow of up to 45 l/min and up to 27 l/min at 3.2 bar for up to 11 minutes — before settling to a continuous boosted flow of 12 l/min at 3 bar until the vessel recharges. The 300-litre vessel provides 180 litres of useable working capacity. Variable speed inverter technology means the pump only generates the pressure your mains can’t already deliver, keeping running costs to a genuine minimum. Operation is measured at a quiet 40 dB(A), and the pump sits on a WaterBoost QuietPad anti-vibration base so nothing transmits through joists or floorboards. WiFi via the DConnect app enables remote monitoring and control. A mains bypass fits in seconds using 2 clips if the unit ever requires attention.

WRAS approved product. Fully sealed system — zero air contact with stored water, no hygiene management required. Completely maintenance free. Suited to 2-4 bed homes upwards, combi-boiler properties and unvented cylinder systems. 5-year tank warranty, 3-year pump warranty. Step down to the ATX-250H for smaller properties. Got the headroom for an upright? See the ATX-300 or ATX-450.