3800 PSI 3.5 GPM 1" Triplex Pressure Washer Pump

Commercial-Grade Power. Built for Long-Run Performance.

The pressure washer is a powerful cleaning tool that utilizes a triplex pump to deliver high-pressure water for various cleaning tasks. With its ability to adjust pressure and flow rate, it is an ideal machine for both residential and commercial use. The triplex pump, such as those found in Simpson pressure washers, is a key component that sets these units apart from others. In this section, we will explore the features and benefits of pressure washers, including their applications, maintenance, and safety precautions.

When you need maximum pressure, higher flow, and industrial-grade durability, the 3800 PSI 3.5 GPM 1” Triplex Pressure Washer Pump delivers. Built for contractors, pressure washing professionals, and serious users who won’t compromise on performance, this powerhouse pump brings dependable cleaning force to the most demanding applications.

With a 1-inch horizontal shaft, this triplex pump is made to pair with gas engines found in heavy-duty pressure washer frames. It delivers up to 3.5 gallons per minute at 3800 PSI, making it ideal for large surface cleaning, fleet washing, concrete restoration, paint prep, and more. Featuring a high-efficiency triplex design, external unloader valve, and a 2-year warranty, this pump offers superior strength, precision pressure control, and peace of mind—all in one rugged package. The pump is also easy to install and operate, ensuring that even first-time users can get started quickly.

Whether you’re upgrading a commercial rig or replacing a worn-out unit, this pump provides the flow, control, and durability to take on tough jobs day after day. It makes various cleaning jobs easier and more efficient, allowing you to complete tasks with minimal hassle.

Engineered for Demanding Jobs

The 3800 PSI 3.5 GPM Triplex Pump is designed from the inside out for high-performance use. Triplex pumps are the gold standard in the pressure washing industry, built with three plungers and a crankshaft-driven piston design that ensures smooth, reliable output—even at high pressures. Customers have found that this pump works just fine, exceeding expectations in various demanding scenarios.

This particular model features:

• Maximum Pressure: 3800 PSI

• Maximum Flow Rate: 3.5 GPM

• Pump Type: 1” horizontal shaft triplex plunger pump

• Max Operating Temperature: 60°C / 140°F

• Weight: 14 lbs

• Warranty: 2 years

Whether you’re blasting through years of grime on concrete or maintaining a fleet of trucks, this pump gives you the raw cleaning power you need—with industrial longevity to match. Customers consistently mention how well the pump is working in various high-pressure scenarios, highlighting its reliability and performance.

1" Shaft Compatibility

Designed with a 1-inch horizontal shaft, this pump is a perfect match for large-frame gas engines, such as those from Honda GX390, Kohler, Vanguard, and similar models. The larger shaft diameter supports higher torque, allowing the pump to handle larger volumes and pressure levels without stress.

Installation is straightforward—just mount the pump to the engine crankshaft using compatible hardware and align your hoses and unloader. You might need to make a bit of minor adjustments during installation, but within minutes, you’ll have a fully upgraded pressure washing setup.

High-Volume Cleaning Power

One of the defining advantages of this pump is its high flow rate of 3.5 GPM, which enables faster rinsing, deeper cleaning, and more effective detergent application. Combined with 3800 PSI of pressure, it delivers the kind of power that makes short work of:

• Heavy equipment degreasing

• Large concrete pads and sidewalks

• Paint stripping and surface prep

• Industrial facility maintenance

• Graffiti and gum removal

• Fleet and truck washing

• Agricultural equipment cleaning

The high-volume cleaning power makes this pump worth the investment.

You’ll move faster, work more efficiently, and tackle more surfaces in less time.

Triplex Design = Longer Life

Triplex pumps are the preferred choice in professional applications for a reason: they last longer, run cooler, and improve performance and reliability under pressure. This pump uses a three-piston crankshaft design that reduces pulsation and increases stability. Key benefits include:

• Consistent water pressure for a smoother spray pattern

• Lower wear and tear compared to axial or wobble pumps

• Better seal integrity, reducing leaks and maintenance needs

• Serviceable components for long-term value

If you’re upgrading from an axial pump or other budget-grade unit, you’ll immediately notice the difference in smoothness, reliability, and pressure stability.

External Unloader for Precision Control

This pump includes an external unloader valve, giving you maximum control over pressure settings while helping protect the pump from overpressure and heat buildup. Unlike internal unloaders, external systems allow:

• Faster pressure adjustments

• Easier maintenance and replacement

• Improved cooling and flow regulation

• Extended pump lifespan

Whether you're operating with long hose runs or switching between different nozzle sizes, the external unloader ensures you always have the right pressure dialed in for the task.

Built to Withstand the Elements

Built with premium components, the pump is engineered to operate in a wide range of environments and temperature conditions. Key durability features include:

• Heat Resistance: Rated to operate at up to 60°C / 140°F, making it suitable for warm water use and hot summer environments.

• Heavy-Duty Construction: The pump’s materials are designed to resist corrosion, high pressure fatigue, and long-term wear.

• Low Maintenance: Thanks to the triplex design and serviceable components, maintenance intervals are longer and repairs are more straightforward.

• 14 lb Weight: Solid but manageable, making it suitable for mounting on carts, trailers, or custom builds.

This pump is built to last—whether it’s exposed to rain, vibration, or daily jobsite demands. It handles these environmental challenges without any problem.

Compatible With High-Performance Accessories

The high PSI and GPM output of this pump make it fully compatible with a wide range of commercial accessories, allowing you to add various accessories for enhanced functionality, including:

• Surface cleaners

• Turbo nozzles

• Extension wands

• Chemical injectors

• High-pressure hose reels

• Foam cannons and detergent systems

If you’re building a professional-grade rig or outfitting a trailer setup, this pump gives you the reliable output you need to power every attachment in your arsenal.

Applications

Pressure washers have a wide range of applications, from cleaning driveways and sidewalks to washing cars and boats. They are also useful for cleaning outdoor furniture, grills, and other equipment. The triplex pump in these units provides a high level of pressure and flow rate, making them ideal for heavy-duty cleaning tasks. With the ability to adjust pressure and flow rate, users can customize the machine to suit their specific needs. Whether you’re a homeowner or a professional contractor, a pressure washer with a triplex pump is a great unit to have in your arsenal.

Specifications Summary

• Max Pressure: 3800 PSI

• Max Flow: 3.5 GPM

• Pump Type: Triplex plunger pump

• Shaft Size: 1” horizontal shaft

• Max Water Temp: 60°C / 140°F

• Unloader: External

• Weight: 14 lbs

• Warranty: 2 Years

These specifications are comparable to those of a Cat pump, known for its reliability and performance in pressure washing equipment.

Installation Notes

To install this pump, ensure the engine you’re pairing it with has a compatible 1” horizontal output shaft running at a standard 3400 RPM. For those who have bought this pump, align it with the shaft, secure with proper mounting bolts, and attach your inlet and outlet hoses. Be sure to follow torque specs and pressure washer startup guidelines to ensure long life and safe operation.

Maintenance and Repair

To ensure the longevity and performance of your pressure washer, regular maintenance is essential. This includes checking and replacing filters, oil, and other wear parts as needed. It’s also important to store the unit properly and perform routine checks on the pump, engine, and other components. Replacing parts, such as the unloader valve or nozzle, can be done easily with the right tools and knowledge. By following the manufacturer’s instructions and taking proper care of your machine, you can enjoy years of reliable service and efficient cleaning.

Safety Precautions

When operating a pressure washer, it’s essential to take safety precautions to avoid injury or damage. Always wear protective gear, such as gloves and safety glasses, and ensure the area is clear of debris and obstacles. Be cautious when adjusting the pressure and flow rate, as high pressures can cause damage or injury. It’s also important to follow the manufacturer’s instructions and guidelines for use, and to never point the nozzle at people or animals. By taking these precautions, you can ensure a safe and effective cleaning experience.

Reliable Warranty for Peace of Mind

With a 2-year manufacturer warranty, you can buy this pump with confidence. It’s backed by a commitment to quality and supported by knowledgeable service teams who understand the needs of commercial users.

Should you encounter any issues, you’re covered—making this not just a powerful pump, but a smart investment.

If you’re ready to upgrade your pressure washing capabilities with a pump that delivers real commercial power, the 3800 PSI 3.5 GPM 1” Triplex Pressure Washer Pump is the answer. With its high flow, high pressure, rugged construction, and long-term warranty, it’s designed for those who demand more from their equipment—and refuse to settle for less.

Boost your performance. Extend your reach. Power through the toughest jobs with confidence.