Pressure Accumulator Tank
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A pressure accumulator tank is a small pressure vessel fitted in the water line between the pump and the taps. A rubber bladder stores a small volume of pressurised water, dampening pump pulsation, extending pump life, and providing instant flow without the pump cycling on and off for every small draw.
Typical sizes for van builds: 0.3–0.75 L. Pre-charge air pressure: 0.5–1.0 bar (set just below the pump cut-in pressure). Without an accumulator, a diaphragm pump cycles every 2–5 seconds during use, causing annoying pulsation and premature wear. Materials must be food-safe (NSF/FDA approved). Install as close to the pump outlet as possible.
FAQ
Is a pressure accumulator necessary in a van water system?
Not strictly required, but strongly recommended. Without one, the pump activates every time even a small amount of water is drawn — typically cycling every 2–5 seconds — causing pulsation and shortening pump life. A 0.75 L accumulator costs ~€15 and significantly improves comfort and pump durability.
What pressure should the accumulator be pre-charged to?
Set the air pre-charge slightly below the pump cut-in pressure — typically 0.5–0.7 bar for a 1 bar pump system. Check with a Schrader valve gauge (same type as a car tyre valve). If the pre-charge is too low, the bladder over-expands; too high and the accumulator provides no benefit.
