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Simpson ALH4240 Aluminum Commercial Pavement Cleaning 4200PSI Pressure Washer

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SKU: ALH4240 / 60688
Quick Overview: 
  • Direct Drive Engine to Pump
  • 4200 PSI @ 4.0 GPM
  • HONDA® GX390 engine with low oil shutdown
  • CAT PUMPS® Industrial triplex plunger pump
  • Aircraft grade Aluminum Chassis
Simpson 4200 PSI Aluminum Pressure Washer
List price: $1299
Free Shipping to lower US 48
Estimated Dates To Leave Warehouse: 

Nov. 25 - Nov. 26

In Stock


Properly cleaning asphalt before you sealcoat, is the single most important thing you can do outside of buying a quality asphalt sealer.  If you're a professinal sealcoater and prefer to pressure wash instead of brooming, the Simpson ALH4240 is one of the best pressure washers you can get as a bang-for-your-buck.

The Simpson ALH4240 is an aluminum pressure washer with a maximum pressure rating of 4200 PSI @ 4.0 GPM which means this thing is built to perform.

When buying a pressure washer for pavement cleaning, the GPM is going to be the single most important factor to consider.  If you're new to pressure washers, you probably think the PSI is the rating to look for and while it is important, the higher GPM rating is going to clean asphalt faster.  4.0 GPM is a really good flow rate and pair that with a 4200 PSI rating, you'll have a powerhouse combination for pressure washing asphalt.

The cart is made from aircraft grade aluminum which resists corrosion to water, making it a fantastic unit that will last for years.  Contractors are tough on their equipment and these units are built to take the abuse.

The ALH4240 is powered by a Honda engine and comes with a 50’ hose, Dial-N-Wash adjustable spray gun and 5 Quick Connect nozzles.

Aluminum vs Steel

Looking for the steel version? We have access to it for phone orders, but before you call us, ask yourself whether you want a chassis that will rust or a chassis that will outlast the pump and motor? Water + Steel = Rust which means an Aluminum chassis is the way to go if you want one that will not only last but will stay great looking over the life of your pressure washer. If you really want the cheaper cart, feel free to call us for a comparable steel model. +1(800) 689-2098

Direct Drive vs Belt Drive

This commercial pressure washer is a Direct Drive unit that makes for a great space saver for the casual or occasional pressure washing projects. For more information, check out this great article that explains the differences between direct drive vs belt drive pressure washers.


  • 3 Year limited HONDA GX commercial engine warranty
  • 2 Year limited pump warranty
  • 10 Year limited frame warranty
  • 90 Day limited accessory warranty


  • Monster Hose 3/8" x 50′ is kink and abrasion resistant and equipped with quick connect

  • Dial-N-Wash® adjustable pressure regulator spray gun to adjust pressure from MIN PSI to MAX PSI with a simple twist

  • 5 Quick connect nozzle tips: 0°, 15°, 25°, 40° and Soap

  • Aircraft grade aluminum frame with brushed extruded aluminum tubing

  • 13" Premium pneumatic tires








HONDA® GX390 engine with low oil shutdown


CAT PUMPS® Industrial triplex plunger pump

Pump/Hose Connection

Quick connect


Monster Hose 3/8" x 50′ steel-braided hose

Gun/Hose Connection

Quick connect


31" Steel with quick connect and threaded M22 connection


0°, 15°, 25°, 40° and Soap


Heavy duty aircraft grade aluminum frame with brushed extruded aluminum tubing


13″ Premium pneumatic

Replacement Parts & Accessories

The following are a list of replacement or add-on parts for this product.

Shipping Weight
Weight: 123 lb
Shipping Dimensions
Dimensions: 38 in × 24 in × 38 in