WATER PUMPS/PRESSURE WASHERS

 

Although not needed to make snow if you have a T-gun, pressure pumps greatly increase the amount of snow you can make. From a simple gas powered pressure washer to a custom electric belt driven pump, we'll suggest your options. Before we begin, it is strongly advised to NEVER run your pumps dry without water! Almost all pressure pumps or power washers require water flowing before starting for proper lubrication. Running your equipment dry will surely ruin your equipment!

 

The amount of snow you can make is determined by the flow rate of your pump. Flow rates are calculated in GPM (gallons per minute) which is also the amount of snow you can make. When beginners start looking for a pump, they seem to be more concerned about the Psi (Pressure per square inch). The pressure of the pump is somewhat irrelevant, as long as it meets the minimum requirements which we recommend at least 600 psi for internal/external mix snowguns and 300 psi for fanguns.

 

You will need to determine where your water source will come from (house hold spigot, pool, pond, etc.). Your house hold water supply is under pressure opposed to a pool or pond which you'll need an additional booster pump to deliver the water to your pressure pump unless its gravity fed. Using water from a pool or pond is an added benefit because the water is much colder than well or city water which in return will produce drier, better quality snow. If you are planning to go the reservoir route, be sure to add a filtering device to prevent particles from clogging your snowgun nozzles. The booster pump and filtering device has to match if not exceed the flow rate of your pressure pump.

 

CALCULATING FLOW RATE

 

Now that you know where you'll be getting your water, calculating your available flow rate is important. This should only apply if you plan on building a custom high flow pump setup, or using multiple pressure washers with your water supply. Does it make sense to buy a pump that flows more water than you have available? The oldest proven method is the 5 gallon bucket test. You'll need a clean empty 5 gallon bucket and a stop watch. Fully open the valve on your water source. Start your stop watch as soon as you move the fully flowing water into the bucket. Stop your time when the bucket is full and record your results.  

 

ELECTRIC OR GAS

 

How will you be powering your equipment and for how long? Do you live in an area where noise may be a concern? Electric power washers can be purchased on a tight budget but are made of lesser quality and have very little flow rates. If you plan on making snow for long periods, we suggest you purchase a replacement warranty on an electric power washer. Parts for these pumps don't exist and are nearly impossible to fix. Gas powered pressure washers generally have much higher flow rates than equally if not cheaper electric pressure washers. Unfortunately they require frequent fueling and are very loud. If you go either of these routes you'll run into a few different fittings on your hoses.

Almost every pressure washer you'll find is a direct drive. Meaning the motor's shaft is directly connected to the pumps shaft. This doesn't pose a problem but the pumps' life longevity during extended run periods are reduced. Direct drive pumps were never meant to be ran for countless hours on end. The other type of pumps you'll find are belt driven. Belt driven pumps are highly valued in snow making. Unfortunately new belt driven pressure washers cost thousands of dollars. If you have the dough, then shoot for the moon. Us at Snowpacked aren't so fortunate, so we find used pumps that we build and re-power at the fraction of the price of a new unit. 


Look for a pressure washer with an unloader valve. An unloader valve allows you to adjust the pumps output pressure. It's balanced by an unloader port that is re-directed to the low pressure input of the power washer. If your pressure washer doesn't have an unloader valve, don't worry its not absolutely necessary but you must have the proper nozzles on your snowgun! Below is a picture of a direct drive pump with an unloader valve. Notice the knob to the left of the pump? Turning this knob counter-clockwise will reduce your hose pressure, and turning clock-wise will increase the pressure. Simply, an unloader is a self-adjusting valve containing a spring that's controlled by pressure. If the input/output pressure increases, it becomes re-routed to the low pressure inlet thus balancing the set pressure. When starting a pump with an unloader, its always best to completely "unload" or reduce the pumps pressure. This helps by giving the pump less resistance for easier starting. Not necessary but this pictured pump is missing a pressure gauge. We always recommend a gauge at the pump and a gauge at your snowgun. 

 

 

Custom Builds

Ok so you've decided go big or go home, even on a budget. If you're lucky, building a dedicated snow making pump setup can be just as affordable as a new pressure washer purchase. I've found 5 GPM pumps for as low as $30, with only needing another $60 in parts. If you were to purchase the same pump brand new you're looking at a retail price of $700+. Pretty good huh? If you're mechanically inclined and have the tools, then a custom build may be the route to go. But you still need a motor, whether gas or electric and the proper plumbing fittings. Always use brass or stainless steel fittings, along with teflon tape on the threads. Never try to tighten brass fittings to a point where you can't turn anymore. Brass is a soft metal, and can be easily snapped.

There are many manufacturers of high pressure pumps. We at Snowpacked prefer Cat Pumps, generally because old used pumps are cheap, parts are readily available, and there isn't much specialty tools you'll need to service them. Other manufacturers include AR North America, Arimitsu, Comet, General, Giant, Hydra-Cell, and Hypro.

We can't offer you any guidance on how to rebuild a pump  or what parts you'll need. Try searching for the pump model and you should easily find a schematic from the manufacturer. Along with the pump breakdown you'll need to find

  • Flow Rate
  • Maximum Pressure
  • Maximum RPM
  • Shaft Size/Diameter
  • Input/Output connections


We've already covered flow rate and the pressures you're trying to achieve. Never spin the pump beyond its maximum RPM (revolutions per minute). Your Shaft size/bore must match your pulley size for the pump. The input/output connections are for your low and high pressure fittings for the pump.

Calculating Pump Horsepower Requirements

Now you'll need to determine how you'll power the pump. Power is generally expressed here in America as horsepower. Keep in mind there is a difference between electric motor (aka electric brake) horsepower and gas motor horsepower. An electric motor's horsepower rating is almost double the actual rating of an equivalent gas motor. For example, a 5 HP (horsepower) electric motor has the equivalent power of a 10 HP Gasoline motor. This is due to efficiency loss but we won't explain all that here.

An easy formula to figure out what size motor you'll need is provided.

GPM X PSI = horsepower required (electric)

1460

 

Let's look at an example. You acquired a Cat Pump 280 that flows 3.0gpm, maximum 1000 PSI, maximum 1330 RPM, 16.5mm shaft diameter. You have a combo gun that requires 500 psi at the gun's nozzles. Running a 50' x 3/8" pressure washer hose, you'll experience a 25 psi friction loss (Refer to the Pumps & Pulleys page for a friction loss chart). A minimum pressure of 525psi is needed at the pump. For fail save reasons in case you decide to upgrade to a 100' hose we'll say 600 PSI needed at the pump.

3 GPM X 600 PSI = 1.23 Horsepower (Electric)

1460

You won't find an electric motor of that exact rating, so a 1-1/2 HP will have to sacrifice. If you were to decide on a gas motor, you would need a 3 HP gas engine. Always remember, gas ratings are double of your standard electric. Most gas motor's horsepower is calculated in the higher bands, meaning higher RPM. Running these small motors in high throttle isn't the best for the life of the engine and uses much more fuel. When choosing a gas engine, find one that's a bit larger than your requirements.

Now that you know the size of motor required for your pump, we'll explain how to drive it using the motor. Let's take that same example mentioned above. You found a 1-1/2hp electric motor, thats designed to run at 3450 RPM. We now have to spin the pump at a maximum 1330 RPM with a 3450 RPM motor. This is done by variance ratios in pulley sizes on both the pump and the motor. We've provided the formula needed and also a pulley calculator located on the Pumps & Pulleys page.

1293.75 RPM (Pump Speed)             =          8" (Diameter of Pump Pulley)

3450 RPM (Motor Speed)                             3" (Diameter of Motor Pulley)

Notice that the pump speed will be lower than the maximum rated by the manufacturer. That's OK, actually slightly lower manufacturer recommended  speeds are desired. It's better for the longevity to spin your pump at a slightly slower speed. Had we used the same setup rather a 7.75" pulley on the pump we would have a 1335 RPM. Note, the flow rate of the pump will be slightly lower at the lowered speed but at a thousandth of a gallon it won't be noticeable.

Gas engines have an adjustable throttle so your RPMs can vary from 500-3600 RPM. Try to keep them low. We run ours at 2000 RPM giving us enough ponies while sipping gas at the same time. You'll definitely need a tachometer to monitor the motor speed at least once. You can find these on digital timing lights at your local auto parts store. You may only need to use this once so try to find a store that has a tool loaner program. A clamp goes around the spark plug wire and an LCD display shows the engines RPMs. Some timing lights are self powered, but most require a connection to a 12 volt car battery. Once you've reached your ideal engine speed, adjust the throttle screw so its impossible to rev the motor any higher. This prevents any damage to your pump and keeps you from having to use the digital timing light every time. Here's a picture of a common timing light.

 

 

 
Types of Fittings


If you already have a pressure washer its important to know what type of fittings you have or will need. Fittings are located on your wand, hose, and pump. Below are common fittings you'll find.

 

 One of the most common fittings on lower flow rate gas power washers is an M22. These fittings are very easy to identify. The black portion of the fitting is a M22 female. As you can see, it has an o-ring in the middle just past the hexagonal "screw". This actual fitting is a M22 Female to 3/8" NPT female adapter.

 

 

 

 

 

This is a 3/8" NPT male to M22 male adapter.

This is a 3/8" Quick connect to M22 male adapter. On higher quality pressure washers you'll find these type of quick connect fittings.

These are a pair of 3/8" quick connect fittings. The fitting pictured on the left is 3/8" NPT to 3/8" male quick connect. The fitting on the right is a 3/8" female quick connect to 3/8" NPT. If building a custom setup, 3/8" quick connects will be the only fittings you'll need.