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)
Features and Specifications
|Water||Cold (100°F max.)|
|Engine||389cc 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.
Zoom on the Simpson ALH4240
In summary, the Simpson ALH4240 is a heavy duty, commercial pressure washer, that offers an all-around versatile cleaning experience, and also:
- spot cleaning of hard, paint-free surfaces and out-of-reach areas
- intense cleaning of tough, paintless surfaces
- cleaning of painted and frail surfaces
- applying detergent and cleaning solutions
The Simpson ALH4240's triplex pump, powered by an impressive 389cc (11.7 hp) engine, can provide a pressure of up to 4200 PSI (approximately 70 times more than a standard garden hose) and a flow of up to 4 GPM (CETA-certified values). The Simpson ALH4240 thus has a cleaning power of 16800 Cleaning Units.
The Honda GX390 engine of this gas-powered pressure washer relies on an old-school pull-start mechanism to get started.
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. The main contributors to its weight are its 389cc Honda GX390 engine, the triplex pump and aluminum frame. However, the unit is mobile thanks to its two 13" pneumatic wheels, which add to its movability and allow it to be manipulated smoothly on the job.
The Simpson ALH4240's package includes a spray gun, a wand, a pressure hose, 5 nozzles and a detergent injection feature, with a more detailed description below.
- Soap injection: While the device doesn't feature a soap tank, detergent supply is ensured by a siphon hose. If a soap nozzle is attached, the device will proceed to add the detergent to the water automatically.
- Pressure hose: A neat storage for the included 50 ft ⌀3/8" high-pressure hose is facilitated by a set of convenient hooks.
- Spray gun and wand: The included classic ergonomic spray gun and its steel wand can be easily stored in a side hook.
- Nozzles: The 5 nozzles included with the device, and the respective surfaces which they’re the most suitable for, are shown in the following table.
|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: Stay prepared for any job with Simpson ALH4240's handy storage area, which allows you to neatly store any nozzles and accessories which you may need for the job.
- Safety: Safety of operation is enhanced by a thermal relief valve (which helps to prevent internal pump damage), a trigger lock mechanism (which prevents accidental operation) and a low oil protection.
- Accessories: The Simpson ALH4240 comes with an owner's manual (opens in a new tab) and some basic documentation to get you quickly started. On top of that, you also get pressure regulator, wand, soap hose, oil, pressure hose and spray gun.
- Emissions: The Simpson ALH4240 is NOT CARB-compliant and so you cannot buy it nor sell it in 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.
- Able to deliver a maximum pressure of 4200 PSI, the Simpson ALH4240 is one of the gas-powered products that produce an above average water pressure, in the $1100 to $1500 price range. If the highest possible power of the water stream is your priority, one of the champions in this price range is the Lifan LFQ4515E-Elite with 4500 PSI.
- The water flow of this washer, which reaches up to 4 GPM (gallons per minute) is one of the highest values found in the above-mentioned price range.
- Reaching up to 16800 Cleaning Units (PSI X GPM), the ALH4240 is one of the more efficient amongst its similarly priced peers. In case you are looking for the highest overall cleaning power, in this price range, one of the current champions is the Lifan LFQ4515E-Elite and its 18000 Cleaning Units.
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.
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, but their gas-powered pressure washers are made in the USA. 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.