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Discussion Starter · #1 ·
Wondering what the ideal combination of gpm and psi is for winter washing of grain trailers. Needs to be able to melt some of the ice and snow and get the sand, grit and salt off.

Too much pressure and flow will make it hard to hold the wand for 2 hours. Have 4 gpm and 3500 psi now and need to replace the washer with a new one. Not sure if 5 gpm and 2000 psi is better or 5 gpm and 3000 psi.

They rate these washers in cleaning units, ie. take psi x gpm and that equals cleaning units. So 4 gpm x 3000 psi =12000 units. With that formula 5gpm at 2000 psi is only 10,000 units, but 2 gpm at 6000 psi would be 12,000 units and there is no way that 2 gpm would wash all the snow away at any pressure.

Opinions on whats the best for snow, ice and slush stuck to the truck and trailer. Majority of the use for this pressure washer will be winter cleaning.
 

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I usually find that I like more flow. If 2000 psi doesn't knock enough dirt off 3000 might but you won't have any paint left on anything either.
 

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More gpm washes better than psi. Would try for 5gpm+. If they are hot water models they will wash even better in the cold, be like pulling into a car wash but without having to feed it loonies and toonies.
 

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Discussion Starter · #4 ·
Yes they are hot water machines. Takes 2 hours to wash super b now. It's a job I hate, would like to get the best combination to make the job quicker without making my body feel worse.

Not sure if I have enough power to run the 10 hp motor for 5 gpm at 3000 psi. Seems to take the same power to run 4 gpm at 3000 psi as it does 5 gpm at 2000 psi.
 

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A good example of less water volume but decent pressure is of those "home owner" type pressure washers that run on a 120 volt 15 amp outlet with something like 1.2 gal as they seem useless to drill through anything such as mud compared to a real pressure washer even more on the lower end of the scale at 1500 psi and 3+ gallons output for an example. The more water volume one can have seems to bring the pressure washer action alive just like a relatively low pressure fire hose because of the sheer volume of water.

What surprises me is that you haven't had paint flying in all directions when you were using your 3500 psi washer and I wonder if the nozzle fan angle was wider so as not being as aggressive as it would have been with a narrower angle. Also did your wand have the slight bend at the end where the nozzle screws on as the longer the wand is, the worse it becomes to fight against that thrust and expect that is part of the reason they go with straight wand ends at truck washes.

If you could get a fair demo of a side by side comparison of models, actual washing conditions on a Super B, then it would probably answer the question pretty quickly.
 

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Discussion Starter · #7 ·
I run a straight nozzle with side handle now. Use the widest fan angle I have. The narrow nozzle would probably take paint off.

Just wasn't sure if the difference between 4 and 5 gpm is even noticeable.

The small home owner units are almost useless.
 
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