Ask working contractors what they run and the answer is usually 4 GPM at 4,000 PSI. It is not a coincidence: that combination is the most capability you can get before the engine, the water supply and the hose all get expensive at once.

The RRV4G40-PKG is AR’s package at that specification: triplex ceramic plunger pump, dual redundant packing, forged brass head, stainless valves, direct drive, boxed with the unloader and fittings.

RRV4G40 specification

• Flow: 4.0 GPM
• Pressure: 4,000 PSI, adjustable
• Speed: 3,400 RPM
• Drive: direct, hollow shaft for engine mounting
• EBHP: 11.0
• Included: unloader, thermal relief valve, inlet filter screen, bypass circuit, fittings and hardware

Which RRV4G40 version to choose

The RRV family at this specification comes several ways, and the difference is the regulator:

• RRV4G40-PKG, the standard package
• RRV4G40-VRT-PKG, with a factory-matched VRT unloader
• RRV4G40-PKG-P, the premium pack
• RRV4G40HDF24-PKG, heavy duty with an F24 flange
• RRV4G40-VRT-HWPKG, the hot water version

If you are adding a heater, take the HW package. A standard package on a hot water system loses its water seals early, and the symptom is a gradual pressure loss that gets blamed on the pump.

Why this specification

Cleaning units, the product of flow and pressure, are 16,000 here. That is a useful number for comparison but it hides the more important point: how the 16,000 is split matters as much as the total.

• 4 GPM drives a 20 in surface cleaner at working speed. At 3 GPM the same tool crawls.
• 4,000 PSI cuts grease and stripped paint without needing a bigger engine class.
• A 420cc engine covers 11 EBHP with margin, and those engines are cheap and available everywhere.
• 4 GPM is the ceiling a garden hose can feed. Above it you need a tank, which is a real change in how the rig is built.

Go higher on either axis and one of those four stops being true.

Pairing an engine with the RRV4G40

11.0 EBHP means 13 HP or more at the crank, which is the 420cc class: a Predator 420 or a Honda GX390. Confirm the shaft is 1 in hollow and horizontal before ordering, because displacement does not reliably predict shaft size.

Do not attempt this pump on a 301cc engine. It will build pressure with the trigger closed and sag the moment a nozzle opens.

What is in the package and why

• Unloader, factory matched to the pump’s flow. This is the part that matters most, because an unloader sized for the wrong flow is the commonest reason a build never reaches rated pressure.
• Thermal relief valve, for the long stretches a contractor spends with the trigger closed.
• Stainless inlet screen, protecting valves and seals from grit.
• External bypass circuit, which keeps recirculating water from heating the pump inlet.

Where the RRV4G40 is used

• Concrete and driveway cleaning: stains, gum, grease and paint
• Fleet washing: semi trucks, buses, delivery vans
• Construction equipment: backhoes, loaders, skid steers
• Agriculture: tractors, barns, poultry houses
• Commercial maintenance: parking lots, shopping centres, municipal sidewalks

RRV4G40 maintenance

• Replace nozzle tips on a schedule. A worn tip drops pressure and passes more water, so the machine feels tired and everyone blames the pump.
• Keep the inlet filter clean. A blocked screen starves the pump and causes the cavitation it was fitted to prevent.
• Oil at 50 hours, then every 300 or three months.
• Seals every 500 to 700 hours on heavy contractor use, replaced before they fail rather than after.
• Pump saver before any freeze.

Building or rebuilding a rig? Send your engine model and shaft size and you will get the right package version.