W4443WH — Bertolini Hot Water Duty Pump | 4060 PSI | 4.3 GPM | Manifold Bypass 190°F | 1″ Hollow Shaft

The W4443WH is the hot water duty variant of the W4443W — Bertolini’s WMG-W Series triplex piston pump rebuilt from the ground up for continuous hot water service up to 167°F (75°C) inlet temperature. What sets the W4443WH apart from every other hot water duty pump in this class is its manifold-integrated bypass regulator — the same continuous-duty brass component machined into the W4443W manifold body — rated independently to 190°F. In hot water applications where the bypass circuit carries the highest thermal load, the W4443WH bypass system runs cooler than the water it handles. Recommended maximum operating pressure in hot water duty service is 4060 PSI (280 bar).

What’s in the Box

• SAE J609-1″ Flange with 4-Bolt and Lock Washer Kit — Everything needed for seamless, rattle-free installation directly to your engine. Grade hardware included — nothing to source separately.
• Fully Assembled W4443WH Pump — Complete with manifold-integrated bypass regulator, adjustable chemical injector, factory break-in oil, and vented dipstick — hot water packing conversion installed and verified before shipment.
• Manifold-Integrated Bypass Regulator — 190°F Rated — Machined directly into the forged brass manifold body. Continuous-duty rated. Adjustable from low pressure to the full 4060 PSI hot water duty maximum. At 190°F thermal rating, the bypass circuit on the W4443WH exceeds the pump’s 167°F inlet rating by a 23-degree margin — the bypass handles the hottest water in the system without thermal degradation of the regulator components.
• Adjustable Chemical / Soap Injector — Factory-installed adjustable downstream injector. Compatible with standard pressure washer detergents and cleaning solutions rated for hot water use.
• Factory Break-In Oil — Crankcase pre-filled with SynPower Gear Oil 75W-90. Replace after 50–100 hours with standard SAE 75W-90 — lifetime oil from that point forward.
• Vented Dipstick — Must be installed prior to field testing. Critical for preventing crankcase vapor buildup during hot water operation. Do not run the pump without it installed.

The 190°F Bypass Advantage

In hot water pressure washing systems, the bypass circuit is the most thermally stressed component in the pump package. Every time the trigger gun closes, bypass water recirculates through the unloader — absorbing heat from the pump head and accumulating temperature with each cycle. On pumps with standard bolt-on unloader valves rated to 140°F or 160°F, this recirculating hot water eventually exceeds the unloader’s thermal limit, causing seal degradation, pressure instability, and premature unloader failure.

The W4443WH eliminates this failure mode entirely. The manifold-integrated bypass regulator — the same continuous-duty brass component used in the W4443W — carries a 190°F independent thermal rating. In a system delivering 167°F inlet water, the bypass regulator has a 23-degree safety margin above the hottest water it will ever handle. Combined with the automatic thermal relief valve that discharges overheated bypass water before it can accumulate, the W4443WH provides a level of hot water thermal management that bolt-on unloader designs cannot match.

Hot Water Packing System

The W4443WH conversion replaces the standard V/U packing with a complete hot water duty seal system:

• Sintek NBR U Packing (Front Seals) — Nitrile butadiene rubber formulated for sustained hot water exposure up to 167°F (75°C). Maintains elasticity and sealing geometry at elevated temperatures, resisting the thermal hardening that causes standard packing to fail prematurely in hot water service. Self-energizing U geometry ensures consistent contact force across the full operating temperature range.
• Inox U Packing (Rear Seals) — Stainless-compatible rear seal for hot water and thermal cycling environments. Engineered for dimensional stability through repeated heat-and-cool cycles.
• Full O-Ring Conversion — Every O-ring in the W4443WH is converted to thermally rated compounds appropriate for continuous hot water duty throughout the entire pump assembly.

Performance

What’s Inside the W4443WH

• Forged Brass Manifold — Increased Wall Thickness — Engineered for elevated operating temperatures with bypass regulator machined into the manifold body.
• Manifold-Integrated Bypass Regulator — 190°F Rated — Continuous-duty, field-adjustable, thermally rated above the pump’s maximum inlet temperature.
• LowStressthread™ Valve Caps — Recessed O-ring design. No Loctite required. Torque reduced by 40%.
• AISI 316 Stainless Steel Valve Assemblies — Mirror-finish, rapid-action check valves for corrosion resistance and fluid dynamic efficiency.
• Sintek NBR U Packing (Front) — Hot water duty nitrile butadiene rubber. Continuous service rated to 167°F (75°C).
• Inox U Packing (Rear) — Stainless-compatible rear seal for hot water and thermal cycling environments.
• Full Hot Water O-Ring Conversion — Thermally rated compounds throughout the entire assembly.
• Solid Ceramic Plungers — High-grade ceramic for uninterrupted high-pressure performance with minimal seal wear.
• Bronze Connecting Rods (One-Piece) — Superior anti-friction performance and extended service life.
• Oversized Crankshaft Bearings — Extended life under heavy continuous-duty conditions.
• Forged Steel Crankshaft — Extended Length — Maximum structural rigidity for solid pump-to-engine coupling.
• Die-Cast Aluminum Crankcase — Anti-corrosion alloy with diamond-tool machined plunger guide surfaces and enhanced cooling fins.
• Ventilated Oil Dipstick — Reduces crankcase vapor risk during hot water operation. Install before first run.

Specifications

Applications

• Hot water pressure washing — continuous-duty contractor operations
• Industrial tank and vessel cleaning with hot water recirculation
• Food processing and sanitation washdown at elevated temperatures
• Fleet washing with hot water supply systems
• Agricultural equipment cleaning with hot water
• Steam-assist and hot water industrial process cleaning
• Multi-shift operations where bypass thermal management is critical

7-Year Warranty

The W4443WH carries Bertolini’s industry-leading 7-year warranty on the pump. Hot water packing systems are subject to normal wear based on operating temperature and duty cycle and are not covered under the pump warranty. Contact WSHPWR for packing service, replacement guidance, and warranty support.