Inspection, Maintenance, and Troubleshooting
Domain focus
Inspection, Maintenance, and Troubleshooting tests the daily checks and diagnostic reasoning that keep a hydroblasting unit safe and productive - and the discipline to stop when a component is out of specification.
Core rules
- Pre-use inspection: hoses for cuts, bulges, blisters, exposed wire, and a current test tag; fittings and whip checks; nozzle orifice with a gauge; deadman function; relief valve; filters; gauges.
- Replace a nozzle when flow rises about 10% or the orifice is visibly worn - a worn nozzle masks itself by lowering pressure.
- Relief valves must be tested and set at or below the lowest-rated component. Never adjust one to compensate for a worn nozzle or a failing seal.
- Maintain water quality to the nozzle manufacturer's filtration specification; clogged inlet filters cause cavitation, fluctuating pressure, and seal damage.
- Keep records: hose test dates, relief valve settings, nozzle changes, and repair history.
Worked example
A unit loses pressure and the gauge fluctuates. Check nozzle size and wear, inlet filter and supply, relief valve stuck open, pump seals and valves, and air entrainment. If the nozzle gauges correctly and the relief valve lifts early, the relief valve is the fault - reset or replace it to specification rather than shimming it shut.
Traps
Raising pressure to hide a worn nozzle; reusing crimped ferrules; skipping relief valve tests because "it never moves"; and replacing a pump before checking the inlet filter.