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High Pressure Wash FAQ

Do you have a question about a pressure washer? Read through our Frequently Asked Questions page to find your answer. If you still have questions, click here to contact our technical support team.

How Much pressure and flow do I need?

Around the house:
To clean around your house, wash your siding, wash your car (Most Coin-Op car washes have about 700psi), or clean your deck you probably only need 1,500 to 2,000 PSI For concrete cleaning or to clean barnacles off boat hulls you would be better off with 3,000 PSI

Commercial / Industrial use:
As a commercial contractor you need at least 3,000 PSI in order to be fully productive.   Flow is important for rinsing horizontal surfaces or powering surface cleaning machines, such as our Hydro Twister. If you are cleaning vertical surfaces, or excess water is a problem, a low flow/high-psi unit is possibly the better option.

For a given amount of horsepower you can only get so much pressure and flow.   Pressure is good for cleaning, but to rinse you need flow to push the dirt across the horizontal surface.  If what you are cleaning comes off easily, but you need to push a lot of dirt -- cleaning animal enclosures or sidewalks for example -- then you need a high-flow unit.  Click here to see our Horsepower Requirements Chart.

What size spray tip do I need? I have a pressure washer rated for 3000 psi and 6 gpm. How do I know what "size" tip to buy?

The spray tip may be the most important part of the pressure washer. They range in size from 2.0 - 15.0. If the tip size is to big, you will experience pressure loss. The same thing happens if you move your thumb over the opening of a running garden hose. The bigger you make the opening of the garden hose, the less pressure you get.

If the spray tip is to small, you may experience the following:

  • Higher pressure
  • Higher amp draw
  • Belt slippage
  • Hotter water discharge
  • Premature motor / pump / unloader wear
  • Less discharge flow
  • Here is the calculation for nozzle size:

Or in you case 3000psi / 6.0gpm SQRT(4000/3000)x6.0


4000/3000 = 1.333

SQRT 1.333 = 1.1547

1.1547 x 6.0 = 6.928

Round up the 6.928 to 7.0

7.0 will be the required nozzle size for this machine.

Do I need a Hot or Cold water pressure washer?

Cold water:
Cold water pressure washers can be used to successfully clean many objects and surfaces through a combination of impact of the spray and the application of cleaning chemicals and soaps. Cold water is generally used where grease and oil are not a factor, but with the right chemicals grease and oil can  still be effectively dealt with.  Consult a Hydro Tek dealer near you for the best advice in the application of cleaning chemicals.

Hot water:
We know from washing dishes that hot water makes cleaning easier, especially if we are cleaning greases, oils, or petrochemicals. Cold water can only be as effective if the proper cleaning chemicals are also used. Hot water can often make cleaning faster by loosening dirt, gum, grease and oil.  Most hot water units use  diesel or kerosene to heat the pressurized water in a heavy duty heating coil. The heating coil and burner system makes the hot water unit much heavier, more complex and more difficult to maintain than a cold water unit. To run the burner system the unit requires electricity.  So unless the unit uses a self-contained power source such as a battery or generator (Like our SC, SS and SM series) , you have to plug the hot water unit in (Like our HG, HD & HN series).

Can I choose a pressure washer on performance alone?

No. The first step in picking a pressure washer is determining how much performance you need to get the job done. How much pressure? How much flow? Do you need hot or cold water? Is gas, diesel or electric power better, safer, quieter, or cheaper. Once you have decided upon these factors, discussed in the other sections, you need to pick a product. Pressure washers with the same power plant will have similar performance, for example an 11 HP gas engine unit will typically produce at least 3,000 PSI and 4 gpm. So it is often difficult to decide between different products except on price. Quality is what sets one pressure washer apart from another. Two pressure washers offered by two different manufacturers may have similar performance in terms of pressure and flow but will be quite different in terms of quality of components and unit configuration. They will also vary in price. When buying a pressure washer, selecting the correct performance for the cleaning job at hand is just the first step. The second step is looking at the quality of construction and the quality of components.

Hydro Tek machines offer advantages over other brands because of their quality construction.  Hydro Tek uses stainless steel for all the control and safety panels.   Our coils are wrapped in stainless steel to prevent rust. Our Ultimate Line uses the quieter, slower running, longer lasting belt drive pumps.  We use stainless steel and heavy duty powder coated steel tubing to make our frames resist rust and outlast the competition.   Our individual components are the best that the market has to offer.  We test all our components extensively before we allow them to become part of our machines.

What is the difference between Vertical and Horizontal Coils?

Most premium pressure washers feature Horizontal style coils while vertical coils can be found on lower cost alternatives. When determining which style to purchase you should consider some of the environmental factors that can affect the burner and coil performance. When exposed to rain, Vertical coils tend to trap small amounts of water at the base of the coil where the burner is located – causing the base plate to rust and potentially causing malfunctions in the burner. Vertical coils typically position the burners closer to the ground than horizontal models leaving the burner open to environmental hazards close to the ground. On a horizontal model you will find that the coil insulation will remain in place while vertical coil insulation can sag over time. Soot is another significant consideration when determining coil orientation. On vertical models gravity can pull soot into the burner nozzles causing a clog and/or poor heating. While on horizontal models, the soot is dropped away from the burner increasing the reliability of the burner. Hydro Tek utilizes Horizontal style coils exclusively on the Ultimate and ProLine machines.

What is the difference between Belt Drive and Direct Drive pumps?

Belt-Drive: Most commonly found on industrial models, a CAT belt driven pump is ideal for cleaning applications requiring 40 + hours of use per week. The belt connecting the engine or motor with the high-pressure pump dissipates the heat and vibration, minimizes the wear and thus the repair on key components, and extends the life of the pump by reducing the RPM demand.
Direct-Drive: For applications not requiring more that 30 hours of use per week, direct driven pumps are more commonly used. The pump is directly coupled to the engine or motor causing the pump to spin twice as fast as the belt drive models. Although these models are not recommended for heavy, consistent usage they are a lower cost alternative to more expensive, belt driven models.

What is more important, Pressure (PSI) or Flow (GPM)?

When purchasing a pressure washer you should consider both the p.s.i. and g.p.m. of the machine. The p.s.i. or pounds per square inch, delivers the "punch" to a washing application and forces the contaminants from the surface. The g.p.m. or gallons per minute will flush the contaminants from the service. Choosing the right combination of p.s.i. and g.p.m. is the key to purchasing the ideal pressure washing system for your cleaning needs.

Why do I need to worry about recycling water from my pressure washer?

First, it is the right thing to do. Protecting the environment is critical to us all. By keeping the earth clean we all benefit by having a better place to live and we leave are children with a better place.

Second, in more and more areas it is becoming the law. Legislation prohibiting contaminated water runoff is on the rise and in order to avoid very hefty fines you must have a plan for containing and disposing of your dirty water.

Hydro Tek has a full line of water recovery, filtration and recycling products.