Choosing A Hi-Pressure Washer
by Steve Spielmann
Choosing a hi-pressure washer can be a confusing experience with all the different pressures and flow rates to choose from. The key to selecting the correct pressure washer is to identify your major application for the equipment and the pressure washing requirements of the application.
Every cleaning application requires a certain amount of water pressure to break the bond between the material to be removed and the surface it is adhered to. Using pressures greater than 20% over the minimum required to break the bond will not improve the work output of the equipment. Once the bond breaking pressure is reached, increasing the water flow will increase the work output of the equipment.
Many people are too oriented to pressure ratings when they think of hi-pressure washers. The term "hi-pressure washer" itself is some what misleading in that it isn't just pressure that gets the job done. Perhaps we should use the term "power washer". It's more accurate.
Let's say the application is to remove grease from a piece of machinery and we need to choose between the Goodway Model GPW-2000 and the GPW-2500. We know that the deposit is soft and not firmly adhered to the surface. Therefore, it should not take a great amount of pressure to break the bond. Assuming that bond breaking pressure is 1,800 PSI, the GPW-2000 is sufficient for the job. If we were to compare the GPW-2000 and GPW-2500 side by side, the GPW-2000 would clean the equipment faster because of its higher flow. The additional 500 PSI of the GPW-2500 is doing nothing to increase the work output of the unit but the additional 0.9 gallons flow of the GPW-2000 is.
One quick way to compare pressure washers in general is to multiply the PSI times the GPM and you obtain a value. Let's call it the "work value". At 2000 PSI and 3.7 GPM, the work value of the GPW-2000 is 7400, (2000 x 3.7). At 2500 PSI and 2.8 GPM the work value of the GPW-2500 is 7000, (2500 x 2.8). This is illustrated by the side by side test results.
Flow or GPM effects the time it takes to clean something. The higher the flow, the shorter the length of time it takes to clean. Pressure of PSI is the force of the water to break the bond of the material from the surface.
Seeking higher and higher pressure ratings when choosing pressure washer or power washers may not give you the best results. Remember, Goodway Sales Professionals are always ready to help you in selecting the right equipment.