Greenhouse Equipment, Automation and Maintenance
This domain tests whether you can specify, calibrate and maintain equipment. The exam rewards preventive maintenance and fault diagnosis over buying more automation.
Equipment and maintenance
- Sensors for temperature, humidity, radiation and CO2; controllers, vent motors, foggers, pumps, filters and fertigation units.
- Calibrate pH and EC probes regularly; clean radiation sensors; check filter pressure differential.
- Keep a logbook for calibration, repairs, spare parts and motor run hours.
- Protect electrical panels from moisture; use RCCB and earthing.
- Automate ventilation and irrigation in zones, but retain manual override for emergencies.
Worked example
A fertigation controller doses acid but pH remains 6.9. Reasoning: possible causes are a drifted pH probe, exhausted acid stock, or a failed injection pump. Check with a handheld meter first, then calibrate or replace the probe; inspect the pump and stock line. Do not increase acid dose blindly, because a probe fault can cause acid burn to roots.
Traps that cost marks
- Trusting an uncalibrated sensor and correcting the wrong variable.
- Bypassing safety interlocks to keep a vent motor running.
- No spare filters or probes, causing crop stress during a breakdown.
- Recording maintenance only in memory, not in a logbook.