The Simpson Aluminum ALH4240 is a gas-powered pressure washer offering a maximum water pressure of 4200 PSI and flow of 4 GPM. (Read full specs)
Zoom on the Simpson ALH4240
The Simpson ALH4240 is a heavy duty, commercial pressure washer, that provides its users with an all-around versatile cleaning experience, and enables:
- spot cleaning of hard, paintless surfaces and reaching far-away areas
- thorough cleaning of hard, paint-free surfaces
- cleaning of painted or delicate surfaces
- applying detergent and cleaning solutions
With an impressive 389 cc (11.7 hp) engine, its triplex pump delivers a pressure of 4200 PSI (roughly 70 times more than a standard garden hose) and a flow of up to 4 GPM (CETA-certified values), resulting in the Simpson ALH4240's cleaning power of 16800 Cleaning Units.
The Honda GX390 engine of this gas-powered pressure washer gets started by a classic pull-start mechanism.
Gasoline storage is facilitated by a steel fuel tank with a maximum capacity of 1.6 gallon.
Design & Handling
The wheelbarrow design of the Simpson ALH4240 grants mobility and stability to the unit. The aluminum frame ensures the device's durability, as it will not rust. The handle adds to the ALH4240 convenience of transport.
The unit's weight of 133 lbs renders its carrying and transportation challenging, as it is far from lightweight. Its 389 cc Honda GX390 engine, the triplex pump and aluminum frame are mainly responsible for its heavy weight. However, the device’s two 13" pneumatic wheels play a key role in its maneuvrability, as they allow it to be manipulated smoothly.
Along with the Simpson ALH4240 itself, the package also includes a spray gun, a wand, a pressure hose, 5 nozzles and a detergent injection feature, which are discussed in further detail below.
- Soap injection: Detergent is fed in through a siphon hose, since the device lacks a soap tank. The detergent will be added automatically to the water when a soap nozzle is attached.
- Pressure hose: The included 50 ft ⌀3/8" high-pressure hose can be neatly stored on the unit when idle thanks to a set of convenient hooks.
- Spray gun and wand: Both the classic ergonomic spray gun and its steel wand may be conveniently stored in a side hook.
- Nozzles: The table below shows you the 5 included nozzles, as well as the surfaces they're the most appropriate for.
|Concrete, brick, masonry||Use with caution||Suitable||Suitable||Suitable||Suitable|
|Siding, gutters, house||Not recommended||Use with caution||Use with caution||Suitable||Suitable|
|Fencing, deck, patio||Not recommended||Use with caution||Use with caution||Suitable||Suitable|
|Lawn equipment, boat, RV||Not recommended||Use with caution||Use with caution||Use with caution||Suitable|
Note: The shape of the nozzles above is for illustration purposes only and may differ.
Red cross: Not recommended. Green check: Suitable. Orange check: Use with caution.
- Dial-N-Wash®: Simpson’s Dial-N-Wash® is an adjustable pressure regulator that allows you to choose a desired pressure for your specific cleaning application. High, medium and low pressure settings can be switched between easily by a simple twist. Its design assures its compatibility with most pressure washer standard spray wands and standard guns with threaded fittings.
- Onboard storage: The Simpson ALH4240's handy storage area lets you store nozzles and accessories, and thus, you’ll be always prepared and have everything necessary for the job at hand.
- Safety: Safety of operation is enhanced by a low oil protection, a thermal relief valve (which helps to prevent internal pump damage) and a trigger lock mechanism (which prevents accidental operation).
- Accessories: Besides the usual owner's manual (opens in a new tab) and documentation to get you promptly started, the Simpson ALH4240 comes with spray gun, wand, soap hose, pressure hose, pressure regulator and oil.
- Emissions: The Simpson ALH4240 is EPA-approved and CARB-compliant. Therefore, the sale and purchase of this pressure washer is permitted in all of the 50 states, including California.
The Simpson ALH4240's performance versus other pressure washers
The following charts are provided to give you an idea of how the key specs of the Simpson ALH4240 compare to similarly priced pressure washers.
- The Simpson ALH4240, which can reach up to 4200 PSI, has one of the higher pressure outputs of the gas-powered units that cost between $1000 and $1300. If your priority is the highest possible power of the water stream, in this price range, we suggest checking out the Lifan LFQ4515E-CA, which reaches up to 4500 PSI.
- With a water flow of up to 4 GPM (gallons per minute), this washer belongs to the best of the above-mentioned price range, as it can deliver a high volume of water.
- Reaching up to 16800 Cleaning Units (PSI x GPM), the ALH4240 is one of the more efficient amongst its similarly priced peers. If you are after the highest overall cleaning power, the Lifan LFQ4515E-CA with its 18000 Cleaning Units is one of the products that can achieve the highest cleaning efficiency in this price range.
As you can see from this interactive chart, when compared to other gas-powered washers between 16500 and 17000 Cleaning Units, the Simpson ALH4240 is on the average side of the price range.
Therefore, this pressure washer nicely fits in the expected budget for this kind of cleaning power.
Features and Specifications
|Water||Cold (100°F max.)|
|Engine||389 cc 11.7 HP Honda GX390 OHV 4-stroke|
|Other model numbers||60688|
|Soap injection||Via siphon hose|
|Nozzles||0°, 15°, 25°, 40°, Soap|
|Quick connect nozzles||Yes|
|Hose||50 ft, ⌀3/8|
(L x W x H)
|Approx. 38 x 23.5 x 26 in|
|Pressure control||Dial-N-Wash® + unloader valve|
|Wheels||2 wheels, ⌀13", pneumatic|
|Included accessories||Oil, steel wand, spray gun, high pressure hose, soap hose, 5 nozzles, Dial-N-Wash® pressure regulator|
|Security||Low oil, trigger lock and thermal relief valve|
Unlike many websites, we did our best to research each of the specs above. That being said, we are not immune to making the occasional mistake or omission. Should you notice any missing or incorrect values, don't hesitate to suggest improvements so we can address the issue.
Simpson has over 50 years of experience making quality products for the outdoor power equipment industry. Part of the FNA Group based in Pleasant Prairie, Wisconsin since 2006, they are a vertically-integrated company, meaning most of the parts and accessories are manufactured and assembled by them. Their manufacturing facilities are international. With the company motto "Driven by Performance", Simpson continues to offer a great variety of pressure-washing systems for the homeowner or the professional contractor.
The Simpson ALH4240 is covered under a warranty for up to 10 years. This warranty may be limited and may not cover all parts of the unit.
For more information about the warranty of Simpson pressure washers, please contact the Simpson Customer Support: 1-877-362-4271.