Hi all. This is for residential snow making and not pressure washing. I have snow making setup that requires pressurized water and compressed air. This misting head device can handle up to 10 gpm but only needs 1000 psi at the most. Most household spigots around here provide 6-8 gpm. I need a pump that can function at the 5-6 gpm rate from household water but I’d like to have the option to run it up to 10 gpm when I have access to a fire hydrant. If I buy a 10gpm pump, can I change it’s running rpm to make it only pull 6 gpm? I would use an 18 hp motor with pulleys so I can change the output rpm. I appreciate any advice. If you are curious about the snow making set up, it’s from Backyardsnowstorm.com the Cold Front unit.
That’s pretty slick!
Just taking a shot at this, why not throttle up/down whatever you use?
Also, run two water hoses into a buffer tank.
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Throttling down would be easy and great if that’s all i would need to do. The lower rpms will reduce gpm as well as psi?
I wasn’t planning on having a water tank. Just directly connecting garden hose.
I’m pretty sure an 18hp motor should be enough to run most any speed at 1000psi. Because the power required goes down the less gpm you’re pushing. So even though you lose some power from the motor as you idle down, you also don’t need as much. And your engine is a bit overpowered for the application, to begin with.
But you could always use a pressure washer power calculator and compare it with the power curve of your motor, just to double check.
Edit: I think maybe I misunderstood the question a bit. If you reduce RPM/GPM, you will also have to reduce nozzle size if you want PSI to remain the same. (Which would be true regardless of what method you use to slow down the pump, whether it’s by pulley size or idling down the motor.)
Ya, my original post might be confusing. What I’m curious about is this: can i hook up a 10 gpm pump to household water that can only supply 6-7 gpm. If i run the pump slower than recommend rpms so it doesn’t out draw the water supply. The snow making nozzles only need 600-1000 psi max. The main reason is to be able to run off of household water and have the ability to hook to a fire hydrant for higher gpm.
My advice would be to rig up some type of a buffer tank if at all possible. 6gpm is still kinda high for a residential spigot to keep up with consistently.
I appreciate your advice and time. I prob should just make a dedicated household supply unit at 5gpm. I was just dreaming of the perfect do-it-all machine.
10GPM @ 1000PSI only needs about 9HP to run and for 6GPM an even smaller engine is needed… double check those numbers but thats what I think I calculated out the other day when I was thinking about this. I’d do a cost analysis and see if it isn’t cheaper to buy two smaller engine/pump combos. Just as an example a Honda GX200 (5.5HP) is around $400 and a GX270 (9HP) is around $650 but a GX630 (20ish HP) is around $1800. So in that regard the two smaller engines is cost saving. This would also allow you to run the engines at full throttle which is much better for the longevity of the engine. I also thought about ways to restrict the flow to bypass the unused water (4 gallons a minute) but that seems like a much more complex and therefore costly option.
I will point out a 10gpm pump is super expensive and quite large so you’ll probably be better off using a 5gpm
