Accumulator Tank
Pressure vessel, expansion vessel, accumulator, pump accumulator, anti-pulsation tank
An accumulator tank is a small pressure vessel connected to the water pump circuit that stores pressurised water, smoothing flow, reducing pump cycling, and extending pump life.
Without an accumulator, the pump starts every time a tap is opened (even for a tiny flow). With one, the pump runs only when the pressure drops below a set threshold, reducing noise and wear. Typically 0.5–2 litres in size.