- PSI and GPM Ratings
- Pump Operations
- A Useful Video on How Triplex Plunger Pumps Work
- Unloader Valves
- Intermittent Use
- Cost Differences and Technical Complexities
Pressure washing is a popular and efficient way to clean a variety of surfaces, from outdoor furniture to concrete driveways. However, choosing the right pressure washer can be a daunting task, especially when deciding between electric and gas-powered models. In this article, we will discuss the key differences between electric and gas pressure washers, including their PSI and GPM ratings, pump operations, unloader valves, and more.
PSI and GPM Ratings
The PSI (pounds per square inch) and GPM (gallons per minute) ratings are important factors to consider when choosing a pressure washer. PSI refers to the amount of pressure that the water is forced out of the nozzle, while GPM refers to the amount of water that flows out of the pressure washer per minute.
Electric pressure washers typically have a lower PSI and GPM rating than gas pressure washers, usually ranging from 1300 to 2000 PSI and 1.2 to 1.8 GPM. These pressure washers are ideal for light to medium-duty cleaning tasks such as washing cars, outdoor furniture, and decks.
On the other hand, gas pressure washers are more powerful, with a PSI ranging from 2000 to 4000 and GPM ranging from 2.5 to 4.0. These pressure washers are ideal for heavy-duty tasks such as cleaning driveways, roofs, and large patios.
According to many of the professional pressure washing forums, GPM is actually a bigger determinate of cleaning power than PSI.
The pump is the most crucial component of a pressure washer, as it is responsible for producing the high-pressure water stream. Electric pressure washers typically have axial cam pumps, which are less expensive and less durable than the triplex plunger pumps used in gas pressure washers. Axial cam pumps are suitable for light-duty tasks and require less maintenance, but they have a shorter lifespan and can be prone to overheating.
Gas pressure washers, on the other hand, are equipped with triplex plunger pumps, which are more expensive but more durable than axial cam pumps. These pumps are capable of producing higher pressure and flow rates and are ideal for heavy-duty tasks. Triplex plunger pumps are also more reliable, however, may require more maintenance than axial cam pumps.
Let’s dive a little deeper into how these two pumps operate:
The Triplex Plunger Pump
A triplex plunger pump, typically found on gas powered pressure washers, is a type of positive displacement pump that is commonly used in high-pressure applications. In addition to gas-powered pressure washers, you’ll also find them in industrial cleaning equipment, and oil and gas drilling operations. The pump consists of three plungers or pistons that are arranged in a triangular pattern and are driven by a crankshaft or camshaft.
The operation of a triplex plunger pump involves a series of four strokes that work together to produce high-pressure water or other fluids. These strokes are:
- Intake Stroke – During this stroke, the plunger is drawn back, creating a vacuum that allows the fluid to enter the cylinder or pump chamber through an inlet valve.
- Compression Stroke – Once the plunger reaches the end of the intake stroke, it starts moving forward, compressing the fluid inside the cylinder and increasing its pressure.
- Discharge Stroke – As the plunger continues to move forward, the high-pressure fluid is forced out of the cylinder through a discharge valve and into the outlet pipe or hose.
- Reversal Stroke – After completing the discharge stroke, the plunger moves back to its starting position, closing the discharge valve and opening the inlet valve to start the next intake stroke.
This continuous cycle of four strokes creates a smooth and consistent flow of high-pressure fluid. The unique design of the triplex plunger pump, with its three plungers and triangular arrangement, helps to reduce pulsation and vibration, resulting in a more stable and efficient pumping process.
Axial Cam Pumps
An axial cam pump, typically found on electric pressure washers, is a type of positive displacement pump that is commonly used in light-duty pressure washer applications. Unlike triplex plunger pumps, axial cam pumps have a simpler design and are less expensive, making them a popular choice for homeowners and small businesses.
The operation of an axial cam pump involves a series of three or four pistons or plungers that are arranged in a radial pattern around a central drive shaft. As the drive shaft rotates, the pistons move up and down in their cylinders, creating a reciprocating motion that generates pressure and flow in the fluid being pumped.
The operation of an axial cam pump can be broken down into the following steps:
- Inlet Stroke – As the drive shaft rotates, the pistons move away from the center of the pump, creating a low-pressure area that draws fluid in through an inlet valve.
- Compression Stroke – As the pistons continue to move outward, they compress the fluid in their cylinders, increasing its pressure.
- Discharge Stroke – When the pistons reach their maximum outward position, they begin to move back towards the center of the pump, pushing the high-pressure fluid out through a discharge valve and into the outlet pipe or hose.
- Reversal Stroke (Optional) – Some axial cam pumps also include a reversal stroke, during which the pistons move inward again to expel any remaining fluid from their cylinders before starting the next cycle.
Axial cam pumps are simple and reliable, but they do have some limitations. Because they are designed for light-duty applications, they typically have lower pressure and flow rates than triplex plunger pumps, and they may not be able to handle very thick or abrasive fluids. Additionally, they can be prone to overheating if run for extended periods of time, so it is important to allow them to cool down between uses.
The Key Difference Between Axial and Triplex Pumps on a Pressure Washer
Triplex pumps have three plungers or pistons that are arranged in a triangular pattern and are driven by a crankshaft or camshaft. These plungers need to be lubricated to prevent wear and damage, as well as to ensure smooth and efficient operation. Triplex pumps are typically lubricated by the fluid being pumped, which serves as both a coolant and a lubricant. This is known as a “wet sump” lubrication system, and it is common in high-pressure applications where the fluid being pumped is oil, water, or another liquid.
In some cases, triplex pumps may also have a separate oil reservoir that provides additional lubrication and cooling for the crankshaft and other moving parts. This is known as a “dry sump” lubrication system and is often used in high-performance applications where the pump is operating at very high speeds or temperatures.
Axial pumps, on the other hand, typically use a self-lubricating design that does not require additional lubrication. The pistons or plungers in an axial pump are made of a low-friction material such as ceramic or graphite, which reduces wear and friction and eliminates the need for oil or other lubricants. Additionally, axial pumps are often designed with a built-in cooling system that helps to dissipate heat and prevent overheating.
A Useful Video on How Triplex Plunger Pumps Work
The unloader valve is a critical component of a pressure washer, as it helps regulate the pressure and water flow rate. Electric pressure washers typically have a fixed unloader valve, which means that the pressure and flow rate are predetermined and cannot be adjusted.
Gas pressure washers, on the other hand, are equipped with adjustable unloader valves, which allow you to adjust the pressure and flow rate according to the task at hand. This makes them more versatile and suitable for a wider range of cleaning tasks.
If you only plan on using your pressure washer occasionally or for light-duty tasks, an electric pressure washer may be the best option for you. They are less expensive, lighter, and easier to maneuver than gas pressure washers. They are also quieter and produce no emissions, making them suitable for indoor use.
Remember the key difference between axial and triplex pumps above? A triplex pump, which is typical for a gas pressure washer, uses the flow of water to cool and lubricate itself. An axial pump, on the other hand, has a self lubricating and cooling system.
This means that a gas pressure washer needs to be in use and spraying while the engine is running. It should not sit idle for more than 10 seconds or so. An electric pressure washer, on the other hand, can idle for much longer because its axial pump is self cooling.
This makes an electric pressure washer better for many chores around the house – washing a car, a deck, a house – that inevitably require small operational breaks. A lot of those things around the house call for more of a soft washing technique anyway. Meaning, even if you had a gas pressure washer, you’d likely need to dial down the GPM and PSI levels to that of an electric pressure washer anyway.
However, if you plan on using your pressure washer for heavy-duty tasks or on a regular basis, like removing oil from asphalt, a gas pressure washer may be a better choice. They are more powerful and durable than electric pressure washers, and they can handle a wider range of cleaning tasks.
Both gas and electric pressure washers should be stored in a safe and secure location where they cannot be accessed by children or pets. It is also important to follow the manufacturer’s guidelines for storage, as different models may have specific requirements.
In general electric pressure washers are smaller than gas. So they take up less space and require fewer steps for appropriate storage.
Gas Pressure Washer Storage
Gas pressure washers should be stored in a dry, cool area away from direct sunlight, moisture, and extreme temperatures. Before storage, the gas tank should be emptied, and the fuel lines should be drained to prevent damage to the carburetor and other internal components.
Follow this link to lean more about winterizing a gas pressure washer, which are the steps necessary to prevent damamge to a pressure washer when it is not being used for an extended period of time.
Additionally, the oil should be changed, and the engine should be run for a few minutes to circulate the fresh oil throughout the system. Gas pressure washers should also be covered with a weather-resistant cover to protect them from dust and debris.
Electric Pressure washer Storage
Electric pressure washers, on the other hand, require less maintenance and storage space than gas-powered models. They stil, however,l need proper storage to ensure their longevity. They should be stored in a dry area away from moisture and extreme temperatures, but the winterization steps aren’t nearly as extensive as they are for a gas pressure washer.
Before storage, the pressure washer should be unplugged, and all the water should be drained from the system to prevent freezing and damage to the pump and hoses. Additionally, the nozzles and spray wand should be removed and stored separately to prevent damage to the tips and threads.
Cost Differences and Technical Complexities
Electric pressure washers are generally less expensive than gas pressure washers, with prices ranging from $100 to $500. They are also easier to use and require less maintenance than gas pressure washers.
Gas pressure washers, on the other hand, are more expensive, with prices ranging from $300 to $1000 or more. They are also more complex to operate and maintain, requiring regular oil changes and tune-ups.
There’s a reason why professional pressure washing companies exist. Because there aren’t many jobs around the house that need the power of a gas pressure washer regularly, so people are willing to pay a professional to pressure wash a tough job every once in a while. Most jobs around the home are suitable for a high quality electric pressure washer.
Some exceptions apply, of course. If you’re on a farm or large property that hosts events regularly, for example, it makes sense to have a heavy duty gas powered pressure washer. Or maybe you’re just the type to have the most powerful and high quality appliance on the market. Gas pressure washers are more durable and long lasting pieces of equipment, as long as they are cared for properly.
For most people, however, an electric pressure washer will do just fine for most jobs around the house, which are often too delicate for a gas pressure washer anyway. They take up less space in your garage and are less expensive.