CIT - Certified Irrigation Technician Certified Irrigation Technician System Maintenance and Repair 1 — Questions and Answers
Question 1: A technician notices that one zone has significantly reduced flow and some heads are not fully popping up. After ruling out a broken lateral line, what is the most likely cause?
- The controller timer is set too short for that zone
- A partially closed or malfunctioning zone valve is restricting flow (Correct answer)
- The sprinkler heads are installed at too steep an angle
- The backflow preventer on an adjacent zone is faulty
Correct answer: A partially closed or malfunctioning zone valve is restricting flow
A partially closed or clogged zone valve reduces water pressure and flow to all heads on that zone simultaneously, causing weak pop-up performance across the board — a telltale sign that distinguishes valve problems from individual head issues.
Question 2: When inspecting a drip irrigation system, a technician finds emitters that are discharging inconsistently — some clogged, others weeping at the base. The first corrective action should be:
- Replace all emitters with a higher-GPH rating
- Flush the mainline and clean or replace clogged emitters (Correct answer)
- Increase system pressure to force debris through
- Install a pressure regulator downstream of each emitter
Correct answer: Flush the mainline and clean or replace clogged emitters
Flushing the mainline removes accumulated sediment and debris. Clogged emitters should then be cleaned with diluted vinegar or replaced — increasing pressure can worsen leaks and damage low-pressure drip components.
Question 3: A backflow preventer on an irrigation system is dripping from the relief valve port during normal operation. This most commonly indicates:
- The inlet shutoff ball valve is fully open
- A worn or fouled check valve seat inside the backflow preventer (Correct answer)
- Excessively low system pressure
- The irrigation controller is sending voltage spikes to the solenoid
Correct answer: A worn or fouled check valve seat inside the backflow preventer
Continuous dripping from the relief port of an RPZ or PVB backflow preventer typically signals a fouled or damaged check valve seat that cannot hold a proper seal, allowing water to bypass and vent.
Question 4: After repairing a broken mainline pipe, the technician should perform which of the following before returning the system to automatic operation?
- Manually activate each zone at full pressure to check for leaks at the repair site and downstream fittings (Correct answer)
- Immediately re-program the controller and run the next scheduled cycle to test
- Apply additional pipe dope to all downstream fittings as a precaution
- Flush the controller's memory and re-enter all zone run times
Correct answer: Manually activate each zone at full pressure to check for leaks at the repair site and downstream fittings
Manually cycling each zone at operating pressure while visually inspecting the repair and adjacent fittings confirms the repair is watertight and that no additional damage occurred during excavation or re-pressurization.
Question 5: A rotor head is rotating in only one direction instead of oscillating back and forth across its arc. The technician should first:
- Replace the entire rotor body
- Check and clean the internal reversing mechanism and ensure the arc adjustment collar is not stuck (Correct answer)
- Increase the zone pressure to at least 60 PSI
- Adjust the controller run time to compensate for incomplete coverage
Correct answer: Check and clean the internal reversing mechanism and ensure the arc adjustment collar is not stuck
Rotors use a reversing gear mechanism and an adjustable arc collar. Debris or a stuck collar prevents the reversal. Cleaning the mechanism and re-seating the collar corrects rotation before any parts replacement is considered.
Question 6: A technician is troubleshooting a zone that activates on its own when no other zones are running and the controller is in the 'off' position. The most probable cause is:
- A shorted solenoid coil allowing constant current flow
- Debris holding the zone valve's diaphragm open (Correct answer)
- A faulty rain sensor overriding the controller output
- Cross-wiring between two zone terminals at the controller
Correct answer: Debris holding the zone valve's diaphragm open
When a zone valve's diaphragm cannot seat fully due to debris (sand, grit, or mineral scale), water pressure alone holds it open and the zone runs continuously regardless of electrical signal — a classic phantom-activation symptom.
CIT - Certified Irrigation Technician Certified Irrigation Technician System Maintenance and Repair 1
A technician notices that one zone has significantly reduced flow and some heads are not fully popping up.
After ruling out a broken lateral line, what is the most likely cause?