Interpump Inside
Four pumps. Every one of them run below its rated limit. That is the whole strategy.
We didn't design our own pump. We didn't need to. Every BossBoys machine runs on one of four genuine Interpump Group models — the Italian manufacturer that has spent almost fifty years becoming the largest maker of high-pressure pumps on earth.
We standardise on the W140, W170, WS201 and WS251 — nothing exotic, nothing proprietary. Interpump Group was founded in 1977 and now exports three-quarters of everything it builds, supplying the pumps inside more professional pressure washers worldwide than any other name in the industry. The part is everywhere, the engineering is proven, and every one we spec is over-specified for what we ask it to do.
A cast-iron crankcase, a solid brass or nickel-plated brass manifold, ceramic pistons — built to run continuously, not in bursts. Look at the spec sheets below and you'll notice the same pattern on every machine: we never run a pump at its rated maximum. Headroom is the whole point. A pump working at 70-80% of what it's rated for is a pump that outlives the machine around it.
That is not a compromise. That is the entire point of building a machine around components engineers already trust, run conservatively, rather than a proprietary part pushed to its limit just to hit a number on a spec sheet.
The Four Pumps
Every model we run, and exactly what it's rated for.
Interpump W140
44 SeriesThe entry-level workhorse — rated for 140 Bar, run at 100 Bar.
- Max Flow Rate
- 12 L/min
- Max Pressure
- 140 Bar / 2,030 psi
- Speed
- 1,450 rpm
- Power Required
- 4.0 hp / 2.94 kW
- Shaft
- 24mm keyed
- Ports
- 1/2" BSP F inlet · 3/8" BSP F outlet
- Manifold
- Brass, 3 ceramic pistons
- Weight
- 7.9 kg
Fitted to our 100 Bar mobile electric and diesel-heated units, running at roughly 70% of its rated pressure for the life of the machine.
Source: Interpump 44 Series technical data (G&S Penrith / Interpump distributor spec)Interpump W170
44 SeriesThe stainless-steel specialist — built for continuous hot-water duty.
- Max Flow Rate
- 9.5 L/min
- Max Pressure
- 170 Bar / 2,465 psi
- Speed
- 1,450 rpm
- Power Required
- 4.0 hp / 2.94 kW
- Shaft
- 24mm keyed
- Ports
- 1/2" BSP F inlet · 3/8" BSP F outlet
- Manifold
- Brass, 3 ceramic pistons
- Weight
- 8.0 kg
Fitted to our 3-phase electric hot water units, where consistent low-RPM running matters more than outright flow.
Interpump WS201
47 SeriesThe all-rounder — the pump behind most of the range.
- Max Flow Rate
- 15 L/min
- Max Pressure
- 200 Bar / 2,900 psi
- Speed
- 1,450 rpm
- Power Required
- 7.5 hp / 5.5 kW
- Shaft
- 24mm male
- Ports
- 1/2" BSP F inlet · 3/8" BSP F outlet
- Manifold
- Nickel-plated brass, 3 ceramic pistons
- Weight
- 14.5 kg
Our most-used pump — specified across petrol and electric machines from 150 to 200 Bar, always with headroom left in reserve.
Source: Interpump 47 Series technical data (Michael Stewart / Jetwave distributor spec)Interpump WS251
47 SeriesThe heavy-duty flagship pump — 250 Bar, engineered for it.
- Max Flow Rate
- 15 L/min
- Max Pressure
- 250 Bar / 3,600 psi
- Speed
- 1,450 rpm
- Power Required
- 10 hp / 7.35 kW
- Shaft
- 24mm male
- Ports
- 1/2" BSP F inlet · 3/8" BSP F outlet
- Manifold
- Brass, 3 ceramic pistons
- Weight
- 14.5 kg
Reserved for our highest-pressure petrol flagship — the same pump platform, built up to run at 250 Bar all day.
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