W4443 — Bertolini WM Series Triplex Piston Pump | 4400 PSI | 4.3 GPM | 1″ Hollow Shaft

The W4443 is the flagship base model of Bertolini’s WM Series — a professional-grade triplex piston pump engineered and manufactured by Idromeccanica Bertolini S.p.A. in Reggio Emilia, Italy. With over 100 years of pump manufacturing heritage dating back to 1918, Bertolini’s WM Series represents the company’s most advanced compact piston pump architecture. The W4443 delivers 4400 PSI at 4.3 GPM at 3450 RPM — the highest flow output in the WMG lineup — and ships exactly as it leaves the Bertolini assembly line. No shortcuts, no substitutions. This is the pump as shown in the Bertolini catalog.

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 W4443 Pump — Ships exactly as it leaves the Bertolini assembly line. No unloader or injector — bare pump configuration. Ready to mount.
• Vented Dipstick — Must be manually installed prior to field testing. Do not run the pump without it installed. Critical for preventing crankcase vapor buildup and protecting the seals during operation.

WM Series vs 3PG Series — Understanding the Seal Difference

Buyers familiar with Bertolini’s 3PG Series will notice that the W4443 uses a different packing seal configuration. The 3PG Series uses Bertolini’s Super-U front seals — a double-U composite system designed for high-pressure longevity in standard cold-water duty. The WM Series, including the W4443, uses a “V” front seal and “U” rear seal system. This is not a downgrade — it is a purpose-built difference in architecture.

The “V” seal in the WM Series is a fabric-reinforced nitrile buna construction engineered specifically for the larger plunger diameter and higher volumetric output of the WMG platform. The nitrile buna compound offers excellent resistance to chemical exposure, detergents, and a wide range of cleaning solutions — making the W4443 particularly well suited for applications involving frequent detergent use or chemical-heavy environments. The fabric reinforcement adds structural integrity under continuous-duty cycling, and the “V” geometry provides a self-energizing seal that tightens under pressure rather than collapsing. Both seal systems are self-lubricating and designed for long service intervals without routine replacement.

The Forged Brass Head — Built to a Higher Standard

The W4443 is built around a forged brass head of increased wall thickness — heavier than the 3PG Series head and engineered to withstand higher operating temperatures without deformation. Bertolini starts with a solid billet of high-grade brass subjected to a precision hot-forging process that aligns the grain structure of the metal, producing a head with higher tensile strength, better fatigue resistance, and zero porosity compared to cast alternatives. Once forged, the head is CNC-machined in Bertolini’s Reggio Emilia facility using fully automated, custom-engineered tooling with inspection and verification at every production stage.

The result is a head that seals perfectly under extreme cyclical pressure loads, operates reliably at elevated temperatures, and does not require Loctite on the valve caps — thanks to Bertolini’s LowStressthread™ recessed O-ring valve cap system that eliminates water pressure from the thread entirely.

Performance

What’s Inside the W4443

• Forged Brass Head — Increased Wall Thickness — Heavier construction engineered for higher operating temperatures and maximum rigidity under overpressure events.
• LowStressthread™ Valve Caps — Recessed O-ring design introduced by Bertolini in 2002. Thread never contacts pressurized water. No Loctite required. Torque reduced by 40%.
• AISI 316 Stainless Check Valves — Mirror-finish, rapid-action valves for corrosion resistance and maximum fluid dynamic efficiency.
• “V” Front Seal / “U” Rear Seal — Fabric-reinforced nitrile buna construction. Self-energizing under pressure. Excellent chemical and detergent resistance. Long service life under continuous-duty cycling.
• Tungsten Carbide-Coated Plunger Rods — Maximum wear resistance and volumetric efficiency across the pump’s service life.
• Bronze Connecting Rods (One-Piece) — Integral one-piece construction in a special bronze alloy. Superior anti-friction performance, lower operating temperatures, and extended service life vs aluminum rods.
• Oversized Premium Bearings — Extended service life even under heavy-duty and continuous-duty conditions including extreme working environments.
• Forged Steel Crankshaft — Extended Length — Increased shaft projection for solid pump-to-engine coupling in any version. Designed for maximum structural rigidity under load.
• 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.
• Ventilated Oil Dipstick — Performance-designed vented dipstick reduces the risk of crankcase leakage due to overpressure vapor buildup.

Lifetime Oil — The EASYlube™ System

Every W4443 ships from Bertolini pre-filled with SynPower Gear Oil 75W-90 — a specially formulated synthetic gear oil with an anti-wear additive package that bonds permanently to all lubricated surfaces. During the break-in period (50–100 operating hours), this oil suspends and removes residues formed inside the crankcase. After the break-in oil change to standard SAE 75W-90 transmission oil, the oil never needs to be changed again for the life of the pump. The LifeTimerod™ stainless steel martensitic plunger guide system — quenched, tempered, and mirror-polished — eliminates wear at the seal contact surface indefinitely, making this a genuine design feature rather than a marketing claim.

Specifications

Applications

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

W4443 vs Comet and General Pump — The Benchmark Comparison at the Base Level

The W4443 competes directly with the Comet ZWD4040G and General Pump EZ4040G — the two professional Italian-engineered triplex pumps that define the benchmark for Honda GX390 direct-drive installations. Both competitors are respected products. Both cost more. The W4443 is $399 delivered — below the entry price of either Comet or General Pump in any configuration — and delivers 4400 PSI at 4.3 GPM versus the 4000 PSI at 4.0 GPM standard those competitors are built around.

W4443 vs Professional Italian Market Standard

More PSI. More GPM. Lower Price. Longer Warranty.

The WMG platform was engineered to exceed the 4000 PSI / 4.0 GPM benchmark — not match it. At 4400 PSI and 4.3 GPM the W4443 outperforms the Comet and General Pump standard on every output metric while coming in below their entry pricing. The 7-year warranty extends two full years beyond what either Italian competitor offers at any price point. For contractors who need the professional Italian pump without the professional Italian markup, the W4443 is the answer.

Run Slower. Save Fuel. Stay Quieter.

A contractor who only needs 4.0 GPM can run the W4443 at approximately 3000 RPM — matching Comet and General Pump rated output while operating the Honda GX390 at a lower throttle setting. Honda publishes GX390 fuel consumption at 0.92 gallons per hour at 3600 RPM under full load. Running at reduced RPM measurably lowers fuel draw, reduces operating noise, and extends engine service life — advantages that contractors running Comet or General Pump configurations at full throttle cannot access.

7-Year Warranty

The W4443 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 across industrial, agricultural, and commercial applications, Bertolini’s commitment to quality is not a promise. It is a track record.