Maintenance, Troubleshooting and Repair of Micro Irrigation Systems
Maintenance and fault finding
This domain tests routine servicing and systematic troubleshooting: low pressure, uneven discharge, clogging, leaks, pump cavitation, valve failure and controller faults. The exam expects a cause-and-effect sequence, not random part replacement.
Core rules
- Routine: flush laterals and submains, clean filters, check pressure gauges and flow meters, inspect emitters, record readings, chlorinate or acidify when water quality demands.
- Diagnose from the head unit outward: source, pump, filter, mainline, submain, lateral, emitter.
- Filter differential pressure above the manufacturer’s limit signals cleaning; a sudden flow drop may be clogging, a closed valve or a broken pipe.
- After any repair, flush the zone before restoring emitters and recheck pressure and flow.
- Keep a log of repairs so repeated failures are visible.
Worked example
A drip block has low pressure at the far end, but the gauge at the head is normal. The technician checks filter differential pressure (normal), then the submain valve (fully open), then a pressure gauge at the submain inlet (normal). The loss appears along the submain. A calculation of friction loss at the measured flow shows it exceeds the design limit. The likely cause is undersized submain or a partially closed valve; the fix is to open/repair the valve or resize the pipe, not to raise pump pressure blindly.
Traps
Do not replace emitters without finding the cause; do not over-chlorinate and damage crops or seals; do not ignore a rising filter differential; do not leave a zone unflushed after repair; do not assume low pressure means a faulty pump.