Does the arrow on my submersible pump refer to direction of impeller rotation, or kick direction?
Usually, a red arrow on the pump refers to direction of kick, a green arrow refers to direction of impeller rotation. However, it is advisable to check the operation manual whilst wiring up a submersible pump.
Can I use recycled water through my high pressure pump for wash down applications?
It’s not best practice, high pressure pumps are designed for clean water only. It depends how clean the water is, however you will have to be prepared for regular mechanical seal or pump replacement. It’s best to exhaust all fresh water options first. If there is no other option then we’d recommend a centrifugal end suction pump over a vertical multistage pump as they are easier to maintain and repair.
Can cavitation be an issue with centrifugal pumps even if I have a far greater NPSHa than NPSHr?
Yes, you can still have discharge cavitation if the required differential pressure is greater than the pump can provide.
The pump isn’t giving me the pressure/flow I need, compared to what you specified it to do. Why would this be?
Check the pump is wired in correctly. If the phases are wired in incorrectly, the pump may run in reverse. This will then only provide around 60% of the specified performance.
What approximate flow of water is required for a typical 4mm dust suppression nozzle?
It depends on the pressure, but at a typical 3 bar, they use approximately 1 cubic meter of water per hour each.