Formula and interpretation
Orifice number per nozzle = GPM per nozzle × √(4000 ÷ desired PSI). Select the nearest standard size at or above the calculation; a smaller opening can raise pressure beyond the target. Surface-cleaner bars require matched tips and even alignment.
Worked example
A four-GPM machine targeting 3,500 PSI through one nozzle calculates near size 4.28. A two-nozzle bar divides flow first: two GPM per tip. Always confirm the manufacturer chart and machine rating.
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