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Product / / 85.149.079B

Comet ZWD-K4042G Pump – 4.0 GPM, 4,400 PSI, 1" Shaft

Comet ZWD-K4042G Pump – 4.0 GPM, 4,400 PSI, 1" Shaft

Specifications

UNLOADER

Built-In

WARRANTY

5 Years

RPM

3,450

PUMP MODEL

Comet ZWD-K4042G

PUMP TYPE

Triplex

Oil Type

30W Non Detergent

Oil Capacity

14 oz

Thermal Relief Value

85.300.024

Max Inlet Temperature

60°C / 140°F

Manifold Type

Brass

Soap Injector

Fixed

Discharge Size

3/8" Brass QC 85.300.103

Inlet Size

3/4" GHF

Plunger Piston

Ceramic

Unloader Type

Built-In

Max GPM

4.0

Shaft Size

1"

Direct Drive

Gas

Weight

17.5 lbs

View full details

PRODUCT

DESCRIPTION

Heavy Duty Triplex Pump for Extreme Cleaning

The Comet ZWD-K4042G Pump Assembly (Bare Pump Part #85.140.079) is a professional grade triplex direct-drive gas pump for contractors, industrial users and property maintenance professionals who need maximum cleaning power. With up to 4,400 PSI at 4.0 GPM this pump gives you the perfect balance of high pressure and water flow for the toughest cleaning jobs.

Built by Comet, a global leader in pressure washer pump technology, the ZWD-K4042G has a brass manifold, ceramic plungers and built-in unloader in a rugged design for long life. Backed by a 5 year warranty it’s a great choice for those who need a reliable long lasting pump for heavy duty use.

Features

  • Bare Pump Part #: 85.140.079

  • Pump Manufacturer: Comet

  • Pump Model: ZWD-K4042G

  • Pump Style: Triplex, direct-drive gas

  • Max PSI: 4,400

  • Max GPM: 4.0

  • Shaft Size: 1" horizontal shaft

  • Unloader Type: Built-in

  • Plunger (Piston): Ceramic for long life

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

  • Discharge Size: 3/8" Brass QC (85.300.103)

  • Soap Injector: Fixed

  • Manifold Type: Brass for heat dissipation and corrosion resistance

  • RPM: 3,450

  • Max Inlet Temp: 60°C / 140°F

  • Thermal Relief Valve: 85.300.024 included

  • Oil Capacity: 14 oz

  • Oil Type: 30W non-detergent oil

  • Weight: 17.5 lbs

  • Warranty: 5 Years

Power and Efficiency in One PumpThe ZWD-K4042G has a triplex plunger design, the industry standard for professional pumps. With three precision engineered plungers the pump runs smoother, reduces vibration and is more efficient than axial pumps.

Delivers 4,400 PSI of maximum pressure to cut through the toughest grime, grease and stains and the 4.0 GPM flow rate for fast coverage on larger cleaning jobs. This balance of pressure and volume is perfect for applications where both cutting power and rinsing are required.

Built for Durability

Durability is at the heart of the ZWD-K4042G design:

  • Ceramic plungers resist heat and wear for long life under heavy workload.

  • Brass manifold increases corrosion resistance, strength and heat dissipation for reliable long life.

  • 1” shaft size for compatibility with commercial grade gas engines.

Weighs 17.5 lbs for solid build quality of a professional grade component but still manageable for installation and maintenance.

Integrated Features for Operator Convenience

The Comet ZWD-K4042G comes with several features to make it more reliable and easier to use:

  • Built-in unloader automatically regulates system pressure to protect the pump and components from overpressure damage.

  • Fixed soap injector for easy detergent application by simply switching to a low pressure nozzle.

  • Brass quick-connect discharge (3/8”) for leak free, secure hose connection that saves time during setup.

  • Thermal relief valve (85.300.024) to protect the pump by releasing overheated water during extended bypass operation.

Maintenance

The ZWD-K4042G requires 14 oz of 30W non-detergent oil to lubricate the internal components. Routine oil checks and scheduled changes are quick and inexpensive maintenance that extends pump life.

Designed to handle inlet water temperatures up to 140°F (60°C) for more flexibility especially for commercial and industrial cleaning applications.

Applications

The Comet ZWD-K4042G Pump Assembly is perfect for heavy duty cleaning jobs that require both power and efficiency. Common applications:* Construction and Industrial Cleaning – Remove concrete residue, heavy mud and grease from machinery and job sites.

  • Fleet and Vehicle Washing – Keep buses, trucks and trailers spotless with high pressure and volume.

  • Agriculture – Clean tractors, harvesters and other farm machinery.

  • Commercial Property Maintenance – Clean large surfaces like parking lots, siding, patios and decks.

  • Surface Preparation – Strip paint, mold and other coatings in preparation for refinishing or repair work.

With 4,400 PSI it’s powerful enough for the toughest grime and 4.0 GPM for efficient rinsing and coverage on large surface areas.

Product Details

  • Part #: 85.140.079

  • Manufacturer: Comet

  • Model: ZWD-K4042G

  • Style: Triplex, direct-drive gas

  • Max Pressure: 4,400 PSI

  • Max Flow Rate: 4.0 GPM

  • Shaft Size: 1” horizontal shaft

  • RPM: 3,450

  • Unloader: Built-in

  • Soap Injector: Fixed

  • Manifold Material: Brass

  • Plunger Material: Ceramic

  • Inlet Connection: 3/4” GHF

  • Discharge Connection: Brass QC 3/8" (85.300.103)

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

  • Thermal Relief Valve: 85.300.024

  • Max Inlet Temp: 60°C / 140°F

  • Weight: 17.5 lbs

  • Warranty: 5 Years

Comet Quality

Comet has been manufacturing reliable, professional grade pumps for contractors and industrial operators worldwide for years. The ZWD-K4042G Pump Assembly continues that tradition with triplex plunger design, brass manifold, ceramic plungers and built-in unloader in a pump for high demand applications.

Backed by a 5 year warranty this pump gives you peace of mind and performance.

When you need maximum pressure, high water flow and rugged durability choose the Comet ZWD-K4042G Pump Assembly – engineered for professionals, 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: