What adjustments would you make if the discharge pressure is too low to meet the requested nozzle pressure?

• A. Close all discharges and reduce RPM.
• B. Increase water temperature.
• C. Verify nozzle size and flow, check for leaks, open more discharges if the supply allows, increase RPM as appropriate or adjust the relief valve setting.
• D. Re-wire the pump.

Answer: (C)

When the discharge pressure is too low to meet the requested nozzle pressure, the aim is to raise the hydraulic energy reaching the nozzles by adjusting pump output and the system setup while making sure the nozzle and lines aren’t being restricted. Start by verifying the nozzle size and the actual flow to the nozzle—an oversized or mismatched nozzle can demand more pressure than the system can reliably provide. Check for leaks in the discharge lines, because any leakage steals pressure and flow that should be reaching the nozzle. If the supply allows, open more discharges to increase the overall flow through the system, which helps lift the pressure at the nozzles through the pump’s characteristic curve. Raise the pump speed (RPM) as appropriate to boost head and flow, and adjust the relief valve setting if the system uses one, so the nozzle pressure target is attainable without causing excessive pressure elsewhere. Closing discharges or reducing RPM would reduce pressure instead of increasing it, changing water temperature won’t fix hydraulic pressure, and rewiring the pump doesn’t address the hydraulic conditions at the nozzle.