3PG4435W — Bertolini Triplex Piston Pump | 4400 PSI | 3.7 GPM | 1″ Hollow Shaft

The 3PG4435W is a professional-grade triplex piston pump engineered and manufactured by Idromeccanica Bertolini S.p.A. in Reggio Emilia, Italy — a company that has been building high-pressure pumps since 1918. The 3PG4435W delivers up to 4400 PSI at 3.7 GPM (at 3450 RPM) and is built exactly as it leaves the Bertolini assembly line — no shortcuts, no substitutions. This is the same pump configuration used by professional contractors, fleet washing operations, and industrial cleaning facilities around the world.

What’s in the Box

• SAE J609-1″ Flange with 4-Bolt and Lock Washer Kit — Everything needed for a seamless, rattle-free installation directly to your engine. Grade hardware included — nothing to source separately.
• Fully Assembled Pump — The 3PG4435W arrives completely assembled with the unloader system and chemical injector with brass barb installed and ready to mount.
• Vented Dipstick — Must be manually installed prior to field testing. The dipstick ventilation system is critical — it prevents crankcase vapor buildup and protects the seals during operation. Do not run the pump without it installed.

The Forged Brass Head — Why It Matters

The most critical component in any high-pressure piston pump is the head — and this is exactly where the 3PG4435W separates itself from lower-cost alternatives. Bertolini starts with a solid billet of high-grade brass and subjects it to a precision hot-forging process under enormous mechanical force. Forging — as opposed to casting — aligns the grain structure of the metal, producing a head with significantly higher tensile strength, better fatigue resistance, and zero porosity. A cast head has microscopic voids and inconsistencies introduced during the cooling process. A forged head does not.

Once forged, each 3PG4435W head is machined in Bertolini’s Reggio Emilia facility using fully automated, custom-engineered CNC tooling. Bertolini equipment is manufactured in state-of-the-art facilities with CNC machining, robots, and high levels of automation, with inspection, testing, and verification at every stage. This level of precision means every port, every valve seat, every thread is cut to exact tolerances — not ground down after the fact to compensate for inconsistencies. The result is a head that seals perfectly, withstands extreme cyclical pressure loads, and does not require Loctite on the valve caps.

Built-In Unloader — Done Right

The 3PG4435W features a built-in unloader valve and fixed 16% detergent injector integrated directly into the head. It’s worth addressing something that professionals in the industry already know: a built-in unloader is not automatically a sign of a quality pump. In fact, many lower-cost manufacturers use an integrated unloader design specifically to reduce parts count and cut production costs — the result is a compact assembly that is difficult to service, prone to pressure fluctuation, and often made from die-cast components that degrade under continuous use.

The 3PG4435W is different. Bertolini’s built-in unloader is machined into the same forged brass head block as the rest of the pump — not a bolt-on afterthought. The unloader circuit shares the same precision-machined tolerances and the same corrosion-resistant materials as the valve system, inlet, and outlet ports. When the trigger gun is released, the unloader bypasses flow smoothly and consistently, protecting the pump, the gasoline engine, and downstream equipment. Adjustable output pressure and a factory-calibrated detergent injector are included as standard — no additional plumbing required.

Performance at Every Speed

The 3PG4435W is designed to run across a range of operating speeds, giving you flexibility to match the pump to your power source. All three speed ratings operate at the same maximum pressure of 4400 PSI.

What’s Inside the 3PG4435W

• Forged Brass Head — 8-bolt crankcase attachment, maximum rigidity under extreme pressure and overpressure events caused by unloader valve malfunctions.
• LowStressthread™ Valve Caps — Bertolini’s patented recessed O-ring design introduced in 2002. The thread never contacts pressurized water, eliminating the risk of loosening during operation. Torque wrench settings are reduced by 40%. No Loctite required.
• AISI 316 Stainless Check Valves — Mirror-finish stainless steel prevents corrosion and maximizes fluid dynamic efficiency. Rapid-action design for easy access during maintenance.
• Super-U Packing Seals — Exclusive double-U self-lubricating composite seal system. Prevents water from contaminating the crankcase oil. Engineered for a long service life without routine replacement.
• Tungsten Carbide-Coated Plunger Rods — Reduces negative surface areas, increases volumetric efficiency, and provides maximum resistance to wear over the pump’s service life.
• Bronze Connecting Rods (One-Piece) — Integral one-piece construction in a special bronze alloy. High resistance to wear, lower operating temperatures, and superior anti-friction performance compared to aluminum rods.
• Oversized Premium Bearings — Extended service life even under heavy-duty and continuous-duty conditions, including extreme working environments.
• Die-Cast Aluminum Crankcase — Anti-corrosion light alloy with an increased number of engineered cooling fins. Diamond-tool machined plunger guide surfaces for maximum smoothness and reduced seal wear.
• Anti-LeakSystem™ — Exclusive Bertolini system between the head and crankcase that prevents dust and debris from entering the packing seal area — extending seal life significantly in outdoor and dusty environments.

Lifetime Oil — The EASYlube™ System

The 3PG4435W ships from Bertolini pre-filled with SynPower Gear Oil 75W-90, a synthetic oil featuring an anti-wear additive that creates a permanent film on lubricated surfaces. During the initial 50-100 hours, it removes residues in the crankcase, and after the break-in oil change, only standard SAE 75W-90 transmission oil is required, which does not need to be changed again for the pump’s lifetime due to the LifeTimerod™ stainless steel plunger guide system designed to eliminate wear.

Specifications

Applications

• Professional pressure washing and contract surface cleaning
• Fleet and heavy equipment washing
• Self-service car wash bay systems
• Pre-painting and surface preparation
• Tank and vessel cleaning
• Industrial process and manufacturing washdown

P4435 vs NorthStar NSZW3540 — An Honest Comparison

If you searched for a direct-drive 4000 PSI pump and found the NorthStar NSZW3540 at Northern Tool, you are looking at a $429.99 pump rated at 4000 PSI and 3.5 GPM with a 12-month warranty. The 3PG4435W is $329 delivered to your door anywhere in the 48 states — $100.99 less — and outperforms it on every published specification.

Side by Side

The Warranty Gap Is the Story

The NorthStar NSZW3540 carries a 12-month parts and labor warranty — standard for a pump at this price point in this channel. The 3PG4435W carries Bertolini’s 7-year warranty. That is not a minor difference in coverage language. It is a manufacturer’s public declaration of confidence in the engineering and materials behind the pump. Bertolini has been building high-pressure triplex pumps in Reggio Emilia since 1918. The 7-year warranty is the outcome of over a century of refinement in forged brass head geometry, seal system design, plunger surface engineering, and crankcase lubrication — not a marketing add-on.

At $329 delivered with more PSI, more GPM, a 7-year warranty, and same or next day shipping, the 3PG4435W is not a compromise. It is the better pump at the lower price.

7-Year Warranty

The 3PG4435W is backed by Bertolini’s industry-leading 7-year warranty — a direct reflection of the confidence Idromeccanica Bertolini S.p.A. places in every pump that leaves its Reggio Emilia production line. With over 100 years of engineering history and millions of pumps operating globally, Bertolini’s commitment to quality is not a promise. It is a track record.