W4443WST — Bertolini WMG-W Series Piston Pump | 4400 PSI | 4.3 GPM | Socket QC Outlet | Tank Feed

The W4443WST is the socket-ready, plumbed version of Bertolini’s WMG-W Series — the industrial-grade triplex piston pump platform that takes everything built into the standard W4443 and adds a continuous-duty adjustable bypass regulator machined directly into the manifold. 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 W4443WST is designed for operators who demand a complete, ready-to-mount pressure system with industrial pedigree, not a price-point pump dressed up with after-market plumbing.

In independent lifecycle testing, the W4443WST platform has demonstrated service life up to five times longer than popular name brands manufactured outside Italy’s industrial pump region. That is not a marketing claim — it is the measurable result of forged brass manifold construction, bronze connecting rods, ceramic plungers, oversized bearings, and a manufacturing culture in Reggio Emilia that has been refining this exact product category for over a century.

What’s in the Box

• Tank Feed Inlet King Hose Barb — 1/2″ M NPT x 1-1/4″ Plated Steel Hose Barb — Factory-installed on the pump inlet port. Designed specifically for gravity feed and tank feed systems. Simply connect a 1-1/4″ non-collapsible inlet water hose directly to the barb — no adapter required. The barbed design prevents hose slippage and fluid leaks under suction load. Hex base allows standard wrenches for installation and accommodates accessory ports. Compact tapered bore for smooth, unrestricted water delivery from tank to pump.
  • Connection: 1/2″ M NPT x 1-1/4″ plated steel hose barb
  • Hose size: 1-1/4″ non-collapsible inlet hose recommended
  • Application: Gravity feed and tank feed systems
  • No adapter needed — assembles directly to pump inlet
• 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 W4443WST Pump — Complete with adjustable industrial bypass regulator, adjustable chemical injector, factory break-in oil, and vented dipstick — installed, pre-lubricated, and ready to mount.
• Adjustable Industrial Bypass Regulator — Manifold-Integrated — This is not an add-on unloader bolted to the outlet port. The bypass regulator on the W4443WST is machined as part of the manifold itself — a single forged brass assembly that handles both pump output and bypass regulation in one continuous-duty rated component. Adjustable from low pressure up to the full 4400 PSI operating maximum. Continuous duty cycle rated — it does not require cool-down intervals, does not degrade under sustained bypass operation, and does not introduce the failure points associated with bolt-on unloader assemblies.
• Adjustable Chemical / Soap Injector — Factory-installed adjustable downstream injector for on-demand detergent draw. Dial in your preferred soap ratio at the injector body. Compatible with standard pressure washer detergents, degreasers, and cleaning solutions.
• AL-QC3/8B — 3/8″ F x 3/8″ F Brass Quick-Connect Socket (Outlet) — Installed on the pump outlet port. Precision-machined solid brass construction. Tool-free connect and disconnect for fast hose and gun changes. Smooth internal bore maintains full system pressure with no flow restriction.
• Factory Break-In Oil — Crankcase pre-filled with SynPower Gear Oil 75W-90. After the break-in period (50–100 hours), replace with standard SAE 75W-90 — and never change it again. Lifetime oil for the life of the pump.
• Vented Dipstick — Must be manually installed prior to field testing. Critical for preventing crankcase vapor buildup and protecting seals during operation. Do not run the pump without it installed.

Why the W4443WST Outperforms Box-Store Competitors

The pressure washer pump market is crowded with products built to a price point — pumps manufactured outside Italy’s industrial pump region using cast manifolds, aluminum connecting rods, standard bearings, and generic packing seals. These pumps work. For a while. The W4443WST is engineered to a different standard entirely.

The manifold-integrated bypass regulator on the W4443WST is a continuous-duty component. Box-store pumps typically use bolt-on unloader valves with plastic or lightweight aluminum bodies that are rated for intermittent use — fine for homeowner applications where the trigger is pulled for ten minutes and the pump sits for a week. In contractor and fleet washing operations where the pump runs for hours and the bypass circuit carries load every time the gun closes, those components fail predictably. The W4443WST bypass regulator is machined brass, integrated into the manifold body, and rated for exactly this kind of sustained use.

The bronze connecting rods, ceramic plungers, and oversized crankshaft bearings compound this advantage. In lifecycle testing, the W4443WST platform has demonstrated up to five times the service life of popular name brands built outside the Reggio Emilia industrial region. Five times longer between packing replacements. Five times longer before bearing service. Five times the return on the initial investment — for operators who run their equipment hard and measure pump life in seasons, not weekends.

WM Series vs Standard Pump Architecture — The Seal Difference

The W4443WST uses a “V” front seal and “U” rear seal system — fabric-reinforced nitrile buna construction engineered for the larger 15mm plunger diameter of the WMG platform. The “V” geometry is self-energizing under pressure, tightening contact force as system pressure increases rather than relying solely on mechanical preload. This makes the seal more effective at high pressure, more tolerant of minor plunger surface variation, and more resistant to the gradual compression set that causes standard packing to begin weeping over time. The nitrile buna compound provides excellent resistance to detergents, degreasers, and chemical cleaning solutions — making the W4443WST well suited for operations involving frequent chemical application.

W4443WST Performance

What’s Inside the W4443WST

• Forged Brass Manifold — Increased Wall Thickness — Engineered for continuous-duty operation and maximum rigidity under overpressure events. The bypass regulator is machined into this same forged body.
• LowStressthread™ Valve Caps — Recessed O-ring design. Thread never contacts pressurized water. No Loctite required. Torque reduced by 40%.
• AISI 316 Stainless Steel Valve Assemblies — Mirror-finish, rapid-action check valves for corrosion resistance and maximum fluid dynamic efficiency.
• “V” Front Seal / “U” Rear Seal — Fabric-reinforced nitrile buna. Self-energizing under pressure. Excellent chemical and detergent resistance. Long service life under continuous-duty cycling.
• Solid Ceramic Plungers — High-grade ceramic for years of uninterrupted high-pressure performance with minimal seal wear.
• Bronze Connecting Rods (One-Piece) — Superior anti-friction performance, lower operating temperatures, and extended service life vs aluminum rods.
• Oversized Crankshaft Bearings — Extended service life under heavy and continuous-duty conditions.
• Forged Steel Crankshaft — Extended Length — Maximum structural rigidity for solid pump-to-engine coupling in any configuration.
• Die-Cast Aluminum Crankcase — Anti-corrosion alloy with diamond-tool machined plunger guide surfaces and enhanced cooling fins.
• Ventilated Oil Dipstick — Reduces risk of crankcase leakage due to vapor buildup. Must be installed prior to first run.

Specifications

W4443WST Tank Feed and Gravity Feed Systems

The “T” suffix designates the Tank Feed configuration. Where standard pump installations draw water from a pressurized supply line, tank feed and gravity feed systems supply water from an elevated reservoir, IBC tote, buffer tank, or open container — relying on gravity head pressure or a low-pressure transfer pump. This is common on trailer-mounted contractor rigs, skid systems with buffer tanks, agricultural washdown setups, and remote job sites where pressurized water supply is unavailable.

The Tank Feed Inlet King Hose Barb installed on this pump accepts a 1-1/4″ non-collapsible suction hose directly — no adapter required. The 1/2″ M NPT x 1-1/4″ plated steel barb locks the hose in place under suction without clamp slippage, and the hex base provides a wrench flat for a leak-free torqued connection. The result is a clean, low-restriction inlet path from tank to pump.

Applications

• Professional contractor pressure washing — continuous-duty operation
• Fleet and heavy equipment washing programs
• Self-service car wash bay systems
• Honda GX and compatible engine direct-drive installations
• Industrial and commercial washdown systems
• Multi-shift operations requiring sustained bypass capability
• Chemical-intensive cleaning environments

7-Year Warranty

The W4443WST is backed by Bertolini’s industry-leading 7-year warranty — the direct result of over 100 years of pump engineering in Reggio Emilia, Italy. For operators who measure equipment by seasons of service rather than weekends of use, the W4443WST is built to earn that warranty and then keep running.