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metabo HWW 4500/25 Inox review

A 24-litre vessel, a mechanical seal system, an electronic pressure switch, and a non-return valve and thread tape in the box.

The bottom line The largest vessel on the shelf at 24 litres, with an electronic pressure switch and — uniquely here — a non-return valve and thread sealing tape supplied in the carton, which are the two parts you otherwise discover you need mid-installation. 4 500 l/h, 48 m of head, stainless housing, stated for one to three sprinklers.

What the maker prints on its own page

A booster set suited to automatic water supply, garden watering and groundwater extraction, as well as pumping, emptying and circulating clean water. A high-quality mechanical seal system and a stainless steel pump housing are stated to give long productivity, and an overload protection guards the maintenance-free capacitor motor against overheating. The high-quality 24-litre pressure vessel allows quiet provision of water, and the electronic pressure switch activates automatically when demand increases. A separate water filling opening makes commissioning easy and a tool-free water drain screw protects against frost. The contents are the booster set, with a maintenance-free capacitor motor, for garden watering with one to three sprinklers, including a non-return valve and thread sealing tape.

The title adds 4 500 l/h and 48 m.

The two things in the box

A non-return valve and thread sealing tape.

Anyone who has installed a booster set knows why that matters. The suction line needs a foot valve or a non-return valve, or the line empties every time the pump stops and the machine has to re-prime — which on an automatic set means it runs and runs and never builds pressure.

And the connections are tapered threads that seal on themselves, which means tape. Without it they weep, and a weeping joint on the suction side lets air in, which stops the pump drawing at all.

Both are small, cheap and absolutely necessary, and this is the only listing on this shelf that supplies either.

24 litres

The largest vessel here.

Vessel size is not about storage, it is about start cycles. Every start is the hardest moment in a pump’s life, and a larger vessel serves more short draws from stored water without the motor running. On a machine expected to last a decade of daily cycling, that is the specification.

One to three sprinklers

More conservative than the five stated by another machine on this shelf, at a similar flow.

Neither is a measurement. What the difference suggests is two makers with different ideas of what a sprinkler takes — and the conservative figure is the one less likely to disappoint.

What is missing

The motor rating, which every other pump here gives. And the suction height — on a booster set often installed on a cistern or a well, that is the figure that decides whether the installation works at all.

Availability

From 208 € to 240 €, that being the spread across the German, French, Italian and Spanish Amazon stores on the day of the survey.

Beyond the euro zone, the British Amazon store prices it in its own currency, which the spread above sets aside.

Listed and unsold: the American Amazon catalogue holds the reference with nobody behind it.

Taken from Keepa on the day this page was last revised; stock and prices move without notice.

Prices quoted in this text were read on 26 September 2026. The live price is at the top of the page.

The declared figures, and the point they stop at

Strengths

  • A non-return valve and thread tape in the box — the two things an installation always lacks
  • The largest vessel here at 24 litres, which means the fewest start cycles
  • A tool-free drain screw stated specifically against frost

Compromises

  • The motor rating is not published, alone on this shelf
  • No suction height, which on a booster set drawing from a well is the binding figure
  • The most expensive machine in the family

Specifications

Flow rate4 500 l/h, at zero head as the convention requires
Head48 m, at zero flow
Motor powerMaintenance-free capacitor motor with overload protection; the rating is not published
Suction heightNot published
ConnectionsNot published — a non-return valve and thread sealing tape are supplied
MaterialStainless pump housing with a mechanical seal system; 24 L vessel
WeightNot published
Amazon referenceB00MX1TZM8 (one reference across 6 Amazon marketplaces)
EAN4007430239501

What this machine usually gets asked

Why is a non-return valve needed?

Because when the pump stops, the water in the suction line wants to run back down. A non-return valve at the inlet keeps the line full so the pump does not have to re-prime every time. On a set that starts and stops all day, it is not optional — and here it is in the box.

Is 24 litres better than 19?

It stores more, so more short draws are served without the motor starting. Since start cycles are what wear these machines out, a larger vessel is a longer life rather than more water.

What is “1 to 3 sprinklers”?

The maker’s own guide to how much the set will supply at once. It is a rule of thumb, not a measurement, and it is a more conservative one than the highest figure on this shelf — which may say more about the maker than about the pumps.

Who this one is for

A permanent installation on a cistern or a well, supplying one to three sprinklers

Guides that feature it

Price and availability

A reference exists on these Amazon stores: France, Germany, Italy, Spain, United Kingdom, United States. Listed is not the same as in stock — availability changes daily.

Details checked on September 26, 2026.

Sources

Specifications: manufacturer sheet and Amazon product page. Prices and availability: Keepa. No product on this site has been physically tested.

How we assess products