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Product / / 85.149.022B

Comet ZWD4040G Triplex Pump – 4.2 GPM, 4,400 PSI, 1" Shaft

Comet ZWD4040G Triplex Pump – 4.2 GPM, 4,400 PSI, 1" Shaft

Specifications

UNLOADER

External 85.300.037

WARRANTY

5 Years

RPM

3,450

PUMP MODEL

Comet ZWD4040G

PUMP TYPE

Triplex

Oil Type

30W Non Detergent

Oil Capacity

14 oz

Thermal Relief Value

85.300.023

Manifold Type

Brass

Soap Injector

Adjustable 85.400.000

Discharge Size

3/8" Brass QC 85.300.108

Inlet Size

3/4" GHF

Plunger Piston

Ceramic

Unloader Type

External 85.300.037

Max GPM

4.2

Shaft Size

1"

Direct Drive

Gas

Weight

25 lbs

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PRODUCT

DESCRIPTION

The Comet ZWD4040G Pump Assembly (Bare Pump Part #85.140.022) is a professional-grade triplex direct-drive gas pump engineered for operators who demand maximum pressure, reliable performance, and long-lasting durability. Delivering up to 4,400 PSI at 4.2 GPM, this pump is designed for high-demand applications such as construction cleanup, agricultural machinery maintenance, fleet washing, and large-scale property care.

Built by Comet, a world leader in pump technology, the ZWD4040G combines a brass manifold, ceramic plungers, and an external unloader in a rugged, serviceable design. Backed by a 5-year warranty, this pump offers unmatched performance and reliability for professional and commercial use.

Key Features

  • Bare Pump Part #: 85.140.022

  • Pump Manufacturer: Comet

  • Pump Model: ZWD4040G

  • Pump Style: Triplex, direct-drive gas

  • Max PSI: 4,400

  • Max GPM: 4.2

  • Shaft Size: 1" horizontal shaft

  • Unloader Type: External (85.300.037)

  • Plunger (Piston): Ceramic for superior wear resistance

  • Inlet Size: 3/4" GHF (garden hose fitting)

  • Discharge Size: 3/8" Brass QC (85.300.108)

  • Soap Injector: Adjustable (85.400.000)

  • Manifold Type: Brass for corrosion resistance and heat dissipation

  • RPM: 3,450

  • Max Inlet Temp: 60°C / 140°F

  • Thermal Relief Valve: 85.300.023 included

  • Oil Capacity: 14 oz

  • Oil Type: 30W non-detergent oil

  • Weight: 25 lbs

  • Warranty: 5 Years

Engineered for Power and Longevity

The triplex plunger design is the professional standard for high-performance pumps. Using three precision ceramic plungers, the Comet ZWD4040G operates with reduced vibration, smoother water delivery, and extended durability.

With 4,400 PSI of pressure and a 4.2 GPM flow rate, this pump delivers a rare balance of raw cleaning power and efficient water volume. The high PSI rating blasts through grease, grime, and tough buildup, while the flow rate ensures faster coverage of large surfaces. This makes the pump ideal for heavy-duty cleaning tasks in industrial, commercial, and agricultural environments.

Built for Durability

The ZWD4040G is constructed with materials and components built to withstand daily professional use:

  • Ceramic plungers resist heat, abrasion, and wear, significantly extending service intervals.

  • Brass manifold adds strength and corrosion resistance while improving heat dissipation to protect seals and components.

  • 1" horizontal shaft ensures compatibility with a wide range of commercial gas engines, making it an excellent replacement pump.

At 25 lbs, the ZWD4040G has the rugged build quality professionals expect from a top-tier triplex pump.

Operator-Friendly Features

This pump includes advanced features that make it more convenient and flexible for the operator:

  • External unloader (85.300.037): Provides precise control over system pressure and makes servicing or replacement easy.

  • Adjustable soap injector (85.400.000): Enables operators to fine-tune detergent delivery, increasing cleaning efficiency.

  • Brass quick-connect discharge (3/8” – 85.300.108): Ensures a secure, leak-resistant connection to hoses and accessories.

  • Thermal relief valve (85.300.023): Protects the pump from overheating during extended bypass operation by automatically releasing overheated water.

Easy Maintenance

The ZWD4040G is designed for simple servicing and long service life.

  • Requires 14 oz of 30W non-detergent oil for lubrication.

  • Oil checks and changes are straightforward tasks that maximize performance and pump life.

  • Designed to handle water inlet temperatures up to 140°F (60°C), it provides flexibility for a variety of cleaning applications.

Routine maintenance is easy, helping ensure that this pump provides years of reliable performance even under heavy workloads.

Common Applications

The Comet ZWD4040G Pump Assembly is designed for the toughest jobs, where high pressure and solid water flow are essential. Its professional-grade output makes it suitable for:

  • Construction Cleaning – Strip away concrete residue, dirt, and heavy mud from equipment and worksites.

  • Fleet and Vehicle Washing – Clean trucks, buses, trailers, and commercial vehicles with speed and efficiency.

  • Agriculture – Maintain tractors, combines, and implements free from grime and buildup.

  • Property Maintenance – Handle large-scale cleaning tasks such as patios, driveways, siding, and walkways.

  • Industrial Applications – Remove grease, oil, and grime from machinery and factory spaces.

  • Surface Preparation – Blast away coatings, mold, and paint before refinishing.

With its high PSI and generous flow rate, the ZWD4040G offers flexibility across multiple industries.

Product Specifications

  • Part #: 85.140.022

  • Manufacturer: Comet

  • Model: ZWD4040G

  • Style: Triplex, direct-drive gas

  • Max Pressure: 4,400 PSI

  • Max Flow Rate: 4.2 GPM

  • Shaft Size: 1” horizontal shaft

  • RPM: 3,450

  • Unloader: External (85.300.037)

  • Soap Injector: Adjustable (85.400.000)

  • Manifold Material: Brass

  • Plunger Material: Ceramic

  • Inlet Connection: 3/4” GHF

  • Discharge Connection: Brass QC 3/8" (85.300.108)

  • Oil Capacity: 14 oz (30W non-detergent oil)

  • Thermal Relief Valve: 85.300.023

  • Max Inlet Temp: 60°C / 140°F

  • Weight: 25 lbs

  • Warranty: 5 Years

Backed by Comet Quality

With decades of expertise in pump technology, Comet is trusted worldwide for building durable, efficient, and reliable pumps. The ZWD4040G Pump Assembly reflects this reputation, offering a triplex design, brass manifold, ceramic plungers, and external unloader in a pump designed for professional-grade applications.

Backed by a 5-year warranty, this pump offers peace of mind and long-term value.

When you need a pump that delivers maximum pressure, reliable flow, and rugged durability, the Comet ZWD4040G Pump Assembly is the professional’s choice—engineered to perform, built to last.

Frequently Asked Questions about Pressure Washers

How to store a pressure washer?

To ensure the durability of your heavy duty pressure washer:

  • Empty the gas tank to prevent fuel from degrading or clogging the engine.
  • Empty the pump and hoses of any remaining water.
  • Perform necessary maintenance before storage.
  • Store in a dry area.
  • Cover.

What is a pressure washer?

A power washer is a cleaning machine that uses a gasoline engine to power a high pressure water pump and nozzle. It’s used to clean driveways, decks, vehicles, outdoor furniture and more by spraying water at high PSI to remove dirt, grime, mold and other debris.Many models also come with a detergent tank for added cleaning power.

How does a power washer work?

A power washer works by drawing water from a connected hose and pumping it through a high pressure nozzle. The gas engine powers the pump which pressurizes the water and then expels it through the nozzle at high speed to clean the surface. The water pressure is measured in PSI (pounds per square inch) and the flow rate is measured in GPM (gallons per minute).Many models also feature adjustable water pressure settings to cater to different cleaning needs. BE makes pressure washing easy with models available for light jobs and heavy duty commercial cleaning projects.

Gas vs Electric power washers?

The main difference is that a gas pressure washer, known for its cleaning power, is powered by a gasoline engine, making it more powerful and portable, while an electric pressure washer is powered by electricity and is generally quieter and lighter.

Gas pressure washers are for heavy duty and large areas due to their durability, whereas electric pressure washers are for smaller jobs.

Your BE electric pressure washer is perfect for smaller jobs and built for portability, and we offer a wide range of electric models. Included with our electric models is a long extension cord for use anywhere around your house.

What to consider?

When choosing a gas pressure washer consider:

  • Pressure (PSI): More PSI means more cleaning power but also more potential for damaging delicate surfaces.
  • Flow Rate (GPM): More GPM means faster cleaning as more water is dispensed.
  • Engine Power: Bigger engines mean more durability and power.
  • Portability: Weight, handle design and wheel size for easier to move.
  • Nozzles: Multiple spray nozzles to adjust the spray pattern for different tasks.
  • Adjustable Nozzle: Allows for fine-tuning the spray intensity and pattern for various cleaning needs.

How much pressure do I need for?

The required pressure (PSI) and cleaning power depend on the surface you’re cleaning:

  • Light duty (car washing, outdoor furniture): 1,300-1,800 PSI.
  • Medium duty (patios, fences, decks): 2,000-3,000 PSI.
  • Heavy duty (driveways, brick walls, large equipment): 3,000+ PSI.

Many pressure washers come with adjustable pressure settings to handle different cleaning tasks effectively.

Can a pressure washing damage surfaces?

Yes, a power washer can damage surfaces if used incorrectly. High pressure water can strip paint, dent soft surfaces or even cause structural damage if the pressure is too high or the nozzle is held too close to the surface. Always use the right PSI for the material you’re cleaning and keep a safe distance from delicate surfaces.

To prevent damage, consider using a model with adjustable pressure settings.

How to maintain your pressure washer?

To ensure the durability and smooth operation of a pressure washer:

  • Change the oil as per manufacturer’s instructions.
  • Clean or replace the air filter to ensure good airflow.
  • Inspect and clean the nozzle regularly to prevent clogs.
  • Drain the gas tank if you’re storing the washer for a long time.
  • Check the hoses for leaks or damage and replace them if needed.
  • Follow regular maintenance requirements to keep the washer in optimal condition.

Can I use a pressure washer in cold weather and low water temperature?

You can use a pressure washer in cold weather but it’s more difficult. The water flow rate in the hoses and pump can freeze and damage the equipment. If you plan to use your pressure washer in cold temperatures make sure to winterize it and store it in a warm area when not in use. You can also use anti-freeze solutions for pressure washers.

Some models are designed to use hot water, which can be particularly effective for cleaning in cold weather.

Do I need any accessories?

Common accessories for power washers: