How to choose the right PSI for certain pressure washing tasks can be problematic especially for beginners. The essential information about what PSI is required for the most common pressure washing jobs and how to efficiently combine it with the appropriate water flow is discussed in detail below.
What Is PSI?
PSI is a pressure measurement unit and its name is an abbreviation of ‘Pounds per Square Inch’. This measurement unit is an essential aspect that pressure washer operators should be familiar with to avoid damaging specific types of materials and surfaces. The PSI of a power washer can be encountered in a unit’s specifications. These specifications usually include the minimum and maximum pressure rates expressed in PSI.
The Best PSI and GPM Combination
The PSI of a pressure washer is not the only indicator of the efficiency of an electric or gas pressure washer for specific cleaning tasks. The GPM, which is an abbreviation of Gallons Per Minute, is another factor that needs to be considered to get the best results. This indicator gives information about how many gallons of water are delivered through the pressure washer nozzle in one minute. If an operator sets a power washer to deliver 2000 PSI, the power of the unit is defined by the GPM value. The higher amount of water the unit can deliver, the more total power it will have.
There is a correlation between the GPM used for a cleaning task and the time needed to finish it. If an operator uses a machine with higher GPM, they will finish faster than while using a lower value if the PSI levels stay the same.
The best GPM for a cleaning task can be summed up as follows:
- Below 2 GPM – ideal for cleaning jobs that require a PSI below 2000 PSI.
- Between 2 GPM and 3 GPM – ideal for cleaning tasks that require a PSI between 2000 and 3500.
- Around 3 GPM or higher – ideal for cleaning tasks that require above 2500 PSI and need a powerful pressure washer.
Damage Due to Wrong PSI Use
Using the wrong PSI levels for a specific cleaning job can lead to different types of damage that sometimes can be irreversible. Pressure washers can be so powerful that they are able to deteriorate even rough materials such as concrete. The use of a PSI that is too low will lead to an inefficient cleaning process that will not deliver high performance in removing dirt or debris. The use of too much pressure, on the other hand, can become dangerous for various types of surfaces.
While pressure washing with a high PSI, the most problematic surfaces are the fragile ones like cars, windows, painted surfaces, and softwood. The damage that can result from using a higher PSI than recommended includes cracked wood, paint strip, damaged window seals, broken window screens, dented vinyl, and more.
Concrete can be permanently deteriorated by too much pressure, especially when using a red pressure washer nozzle that can create deep stripes. Operators that avoid using concrete cleaners and decide to use higher pressure instead are often faced with this problem.
Pressure washing certain types of surfaces using OSI levels that are too high can be dangerous to the operator or to the persons in close proximity because of the small pieces that come off the cleaned surface. These small pieces will be propelled at high pressure and can lead to severe injury, especially if the operator is not wearing protective gear.