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, a heavy duty, commercial pressure washer, gives its user an all-around versatile cleaning experience, topped off by the following features:
- spot cleaning of hard, unpainted surfaces or high reach areas
- intense cleaning of tough, paintless surfaces
- cleaning of painted or delicate surfaces
- application of detergent and cleaning solutions
Powered by a powerful 389 cc (11.7 hp) engine, its triplex pump can deliver a pressure of 4200 PSI (around 70 times more than a standard garden hose) and a flow of up to 4 GPM (CETA-certified values). Combined, these values mean that the Simpson ALH4240 has a cleaning power of 16800 Cleaning Units.
A classic pull-start mechanism is responsible for starting the gas-powered pressure washer’s Honda GX390 engine.
A steel fuel tank with a maximum capacity of 1.6 gallon is used to store gasoline.
Design & Handling
The wheelbarrow design of the Simpson ALH4240 grants mobility and stability to the unit. The aluminum frame allows the device to remain highly durable, as it will not rust. The handle adds to the ALH4240 convenience of transport.
With a weight of 133 lbs, the model is not lightweight. Therefore, it may be challenging to manually carry it around and transport it. The major reasons for its heavy weight are its 389 cc Honda GX390 engine, the triplex pump and aluminum frame. However, the device’s two 13" pneumatic wheels play a key role in its maneuvrability, as they allow it to be manipulated smoothly.
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: Detergent is fed in through a siphon hose, since the device lacks a soap tank. If a soap nozzle is attached, the device will proceed to add the detergent to the water automatically.
- Pressure hose: Using a set of convenient hooks, the included 50 ft ⌀3/8" high-pressure hose can be easily stored on the unit when it is not running.
- Spray gun and wand: A side hook allows for an easy storage of the included classic ergonomic spray gun and its steel wand.
- Nozzles: The 5 included nozzles, and the respective surfaces they’re appropriate for, are listed in the table below.
|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 allows you to be always fully prepared, as it features a handy storage area, where nozzles and accessories can be stored.
- Safety: Safety of operation is enhanced by a trigger lock mechanism (which prevents accidental operation), a low oil protection and a thermal relief valve (which helps to prevent internal pump damage).
- Accessories: Included with the Simpson ALH4240 are also the owner's manual (opens in a new tab) and some basic documentation to get you promptly started, along with several accessories, such as pressure hose, spray gun, oil, pressure regulator, wand and soap hose.
- Emissions: The Simpson ALH4240 is EPA-approved and CARB-compliant. And so, this pressure washer is available for sale and purchase in any 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.
- With a maximum pressure output of 4200 PSI, the Simpson ALH4240 finds itself in the expected pressure range among gas-powered units that cost between $1000 and $1200. As for the device with the most powerful water stream, in this price range, one of the top products is the Lifan LFQ4515E-CA with 4500 PSI.
- With a maximum GPM of 4 (gallons per minute), this washer belongs to the best in terms of water flow, in its respective price range.
- The ALH4240, with its 16800 Cleaning Units (PSI x GPM) sits at the high end of the cleaning efficiency spectrum, when compared to other devices of similar price. 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.