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Pressure Washer FAQs

Pressure Washer FAQs

  • What is a pressure washer?

    A pressure washer is an outdoor power tool that makes cleaning easier by using a high-pressure spray of water to clean a surface. A gasoline engine or electric motor drives a pump, which is supplied by your home’s water supply. The water enters the pump at about 50 PSI, is compressed (and thus pressurized) inside the pump, and exits the pump at as much as several thousand PSI, depending upon the unit. This high-pressure water travels through a hose to a spray gun. The nozzle at the end of the spray gun directs the high-pressure spray as you clean.

    The force of the high-pressure spray loosens dirt and flushes it away. On more professional-grade models, the spray is even powerful enough to strip paint, which is useful in paint preparation. You can use many detergents with a power washer, too, for even more effective cleaning. And there are accessories you can buy that make cleaning even easier.

  • What is “PSI” and “GPM,” and why are they important?

    PSI is short for “pounds per square inch.” It is a measure of the water pressure coming out of the pressure washer. A typical garden hose dispenses water at about 50 PSI, and a coin-operated car wash provides about 700 PSI. A pressure washer, by contrast, typically dispenses water at several thousand PSI, depending upon the model.

    GPM stands for “gallons per minute,” and describes how much water is flowing through the pressure washer.

    You’ll find both of these ratings on a pressure washer, because they’re both important. Together, they provide your pressure washer’s cleaning power. PSI provides the “oomph” you need to lift dirt and grime, and GPM provides the necessary quantity of water to wash it away.

    The real measure of a pressure washer’s cleaning power can be found by multiplying PSI by GPM. The higher the number, the greater the cleaning power. For example, a garden hose delivering water at 50 PSI and 5 GPM has a cleaning power of only 250. A pressure washer, however, delivering water at 2500 PSI and 2.3 GPM has a cleaning power of 5750.

  • How do I select the right pressure washer?

    The first question you should ask yourself is where you intend to use the pressure washer—at home or at work. A pressure washer used primarily at home probably doesn’t need to be as powerful as one that is used on a job site. Around the house, for example, you shouldn’t need more than 3000 PSI. To be fully productive on the job site, though, you probably need at least 3000 PSI.

    Next, ask what you want to clean. If you’re looking to simply take the dirt and grime off the driveway or patio furniture, you can use a unit with a relatively low pressure—perhaps 2500 PSI. If, however, you plan on scrubbing mold and mildew off concrete, or prepping a house for painting, you should consider a unit with a higher pressure.

    Finally, think about how much cleaning you will be doing. If you’re cleaning a number of items, or if you need to clean a large area, you might want to consider a unit with a higher GPM. More water means more cleaning power, and a higher GPM will make the job go faster.

  • How can I get assembly instructions for my pressure washer?

    For assembly instructions, please refer to your owner's manual.  If you no longer have your owner's manual, please visit our support page and enter your serial number.

  • Why isn't my pressure washer starting?

    There are a variety of reasons as to why your pressure washer may not start.  Some of these include, a dirty air filter, lack of or old fuel, problems with the spark plug wire's connection or a bad spark plug, water in the fuel or an excessively rich fuel mixture, or the choke is in the ON position.  Please refer to your owner's manual to determine the solution for each problem.  If you no longer have your owner's manual, visit our support page and enter your product's serial number.

  • What could be preventing my pressure washer from suctioning detergent?

    If the detergent is not suctioning, you may want to check the following; is the detergent siphoning tube submerged properly?  Is the detergent siphoning tube/filter obstructed or cracked?  Is the high-pressure nozzle installed instead of the low-pressure nozzle?  If you are still in need of assistance we recommend reaching out to our customer support team.

  • How do I change the nozzle on my pressure washer?

    To change the nozzle, pull back the "quick release collar" and insert the new nozzle.  Release the "quick release collar" and make sure the nozzle is securely in place.

  • Which nozzle is best for different applications?

    Blast Pressure Nozzle (Red) - Higher pressure and slower flow.  Best used for the following: higher and harder to reach spots (such as second levels), paint removal, oil stains, rust removal, other stubborn substances (tar, gum, grease, wax, etc.)                                     

    Clean Pressure Nozzle (Green) - Medium pressure and medium flow.  Good for most all purpose cleanings (home siding, brick patios, wood decks, driveways, sideways, garage floors, etc.)                                                                                                                               

    Wash Pressure Nozzle (White) - Lower pressure and higher flow.  Good for delicate applications and gentle cleanings of boats, RVs, patio furniture, lawn equipment, etc.

    Detergent Nozzle (Black) - Use this nozzle with pressure washer detergents/soaps only.  This nozzle helps to break down stubborn dirt and grime on a variety of surfaces.

  • How do I use my power broom attachment?

    This attachment is best used on pressure washers up to 4000 PSI to clean driveways, patios, decks and sidewalks.  To switch to this accessory, you do the same actions as you would when you switch to a different nozzle.  First turn your pressure washer and water supply OFF.  You need to de-pressurize the unit by squeezing the spray gun trigger.  Be careful to never place any body parts in front of the direct path of the water stream.  Lock the trigger on the spray gun when it is not in use. Now, change the accessory by sliding the collar away from the collar to disengage the accessory from the inlet plug.  Once the power boom is attached securly, make sure the water broom is positioned towards the surface you intend to clean. Squeeze the pressure washer spray gun trigger.  Now move the power broom in the direction of the spray to losen and force the debris into the collection area. 

  • How do I get started using my pressure washer?

    All pressure washers are to be used outdoors in properly ventilated areas.  Place the pressure washer on level ground and make sure there is at least 5 feet of clearance all around the unit.  All units are shipped without oil in the crankcase.  You will need to add engine oil before starting the unit.  You will also need to verify that the fresh fuel level is correct, that the fittings and couplers are properly secured, that there is proper connection to a sufficient water supply and that the thermal relief valve is rotated and open to ground.  Move the fuel valve lever (B) to the ON position.  For a cold engine, move the choke lever (A) to the CLOSED position.  For a warm engine, the choke lever should be in the OPEN position.  For further instructions, we recommend checking your owner's manual for your unit.  If you no longer have your owner's manual, please visit our support page and enter your product's serial number.
  • Why Generac pressure washers? Isn’t Generac a generator company?

    You’re right—Generac’s primary focus has been designing and manufacturing generators for residential, commercial and industrial applications.

    Nonetheless, back in the early 1990s, we applied our knowledge of air-cooled engines and portable product design to pressure washers—it was a natural evolution. And for the first time power washers were readily available to consumers at a price they could afford. Along the way, we were granted several patents that have since changed the industry.

  • How often does a pressure washer require maintenance?

    All pressure washers require periodic maintenance, such as oil and air filter changes, to ensure maximum performance for years of reliable service. Refer to the owner's manual for routine maintenance procedures and schedules. 

  • What type of oil should I use in my pressure washer?

    An SAE rated high detergent oil means that API Service Class SF requirements for gasoline engines, similar to your car. Refer to your owner's manual for details. To find your owner's manual online, visit our Product Support page and enter your serial number or model number. 

  • How do I store my pressure washer for the winter?

    Long term storage is important, espcially in the winter. It is highly recommended to use Pump Saver to winterize the pump, which prevents damage internally due to freezing water. Full long term storage instructions are included in the unit's manual. To find your manual online, visit our Product Support page and enter your serial number or model number. 

  • Can I use hot water in my pressure washer?

    No, water must be no more than 100°F. Hot water can cause permanent damage to the pump. 

  • Can I use bleach to clean my pressure washer?

    No, bleach can cause permanent damage to the seals and O-rings in the gun, wand, hoses and pump. Use only power washer soap as a cleaning agent. 

  • Can I connect my pressure washer to one of your water pumps?

    No, the pressure washers require a steady source of clean, pressurized water, such as the hose spigot on your home. We do not suggest this, as the water pump is dependent on another source of standing water, which may contain particulates that could damage the power washer, or not enough water to properly supply the power washer.

  • Can I connect my pressure washer to my rain collection bin or retention pond?

    No, the pressure washers require a steady source of clean, pressurized water, such as the hose spigot on your home. It needs a minimum of 3.8 gallons per minute.

  • How do I know which nozzle to use with my pressure washer?

    The nozzles that come standard with the pressure washer all have different spray patterns and intensities. We recommend starting with the lowest pressure nozzle first, and test it in an area for results first. Nozzles that have a higher pressure or tighter spray pattern can easily cause damage to softer surfaces. The description for the nozzles that came with your pressure washer are in your owner’s manual. Owner’s manuals and other documentation can be downloaded from our Product Support Page using the unit’s serial number, or contact us for further assistance.

  • I no longer have my Owner's Manual, how can I get another copy?

    Owner's manuals and other documentation can be downloaded from our Product Support Page using the unit's serial number, or contact us for further assitance. 

  • If I have a problem with my pressure washer where do I go for help?

    Any Authorized Generac dealer can perform warranty service. To find your local authorized Generac dealer see our locator or contact us for additional information. Our Authorized Service Centers provide parts, service and information on Generac equipment, regardless of where it was purchased. Authorized Service Centers are staffed with trained technicians certified in supporting all aspects of the Generac pressure washer line.

  • My pressure washer has erratic pressure, loss of pressure or low water volume.

    What nozzle is being used?  Refer to the unit’s owner’s manual to verify the correct nozzle is being used.  Check the units pump to see if the water inlet filter is blocked, clogged or damaged.  If the screen is damaged, remove and replace. Is the high-pressure hose leaking?  If yes, check the O-rings.  If damaged, remove the old O-rings with a small flathead screwdriver and replace with new ones.  Make sure the garden hose and high-pressure hose are not kinked, leaking, or blocked in anyway and that the water is turned on full force and supplying the correct amount of water outlined in your owner’s manual. If these steps are completed and the washer is still fluctuating, there may be air trapped in the pump.  To bleed the pump of any air, turn the machine off, disconnect the high hose, and trigger gun from the power washer.  With only the garden hose connected to the machine, turn on your water source and allow water to run through the pump of the machine for 20 or 30 seconds.  Turn off the water, connect the high-pressure hose, trigger gun, and try using the machine again.

  • Why does water come out of the pump?

    If an engine runs for several minutes without spraying, the pump will automatically purge water to protect it from overheating.  This is called an automatic cool-down or thermal relief system.

Online Product Support

Looking for more? In Generac's Online Product Support section you can find the specifications, product manuals, frequently asked questions, how-to videos, and more for your product. Enter your model or serial number to go directly to your specific information or find your model through the Product Lookup.