If a deck gun flow is not as expected, what checks would you perform?

• A. Confirm water supply, verify valves are fully open, check for air in lines or obstructions in discharge, inspect check valve
• B. Replace deck gun
• C. Change pump oil
• D. Increase discharge pressure until expected

Answer: (C)

When deck gun flow is not as expected, focus on the water path and control settings. Start by confirming the water supply is adequate and that all valves in the supply and discharge path are fully open, since any restriction here immediately reduces flow. Then look for air in suction or discharge lines and for obstructions along the path, because trapped air and debris or kinks can markedly lower or wobble the flow. Finally, inspect the check valve to ensure it isn’t stuck or leaking, as a faulty check valve can block forward flow or cause recirculation that diminishes what reaches the deck gun. These checks hit the common, fixable causes of reduced flow. Actions like changing pump oil or forcing a higher discharge pressure don’t address the upstream path and can mask or worsen the symptom rather than resolve the issue.