CIT - Certified Irrigation Technician System Maintenance and Repair 2 — Questions and Answers

Question 1: A sprinkler head is not retracting fully after the zone turns off. The most likely cause is:

The controller has a programming error
Dirt, debris, or a worn spring in the sprinkler body preventing the riser from retracting (Correct answer)
The water pressure is too high
The backflow preventer is malfunctioning

Correct answer: Dirt, debris, or a worn spring in the sprinkler body preventing the riser from retracting

A sprinkler head that doesn't retract properly usually has dirt or debris between the riser and the body, or the internal spring that forces the riser down has weakened or broken. Cleaning the head and replacing the spring (or the entire head) resolves the issue.

Pop-up sprinkler heads rely on an internal spring to retract the riser when water pressure drops. Over time, dirt and sand entering the gap between the riser and body can cause binding, and the spring can weaken from constant compression cycles. Troubleshooting steps: (1) Pull the riser up manually and check for gritty resistance. (2) Flush the head by running the zone with the nozzle removed. (3) If the riser is still sticky, remove the head and disassemble for cleaning. (4) Check the spring — if it's corroded, kinked, or weak, replace it. (5) If the body is scored or damaged, replace the entire head. Non-retracting heads are vulnerable to mower damage and trip hazards, making this a priority repair.

Question 2: During a spring startup of an irrigation system that was winterized by blowout, the technician should:

Turn on the water full blast to test the entire system at once
Slowly open the main water supply, allowing pipes to fill gradually, then test each zone individually for leaks and proper operation (Correct answer)
Only test the first and last zones
Immediately set the controller to the summer schedule

Correct answer: Slowly open the main water supply, allowing pipes to fill gradually, then test each zone individually for leaks and proper operation

Spring startup requires gradually filling the system with water to prevent water hammer and allow the technician to identify any damage from freezing, settling, or other winter events. Each zone should be tested individually for leaks, head alignment, and proper operation.

A professional spring startup procedure includes: (1) Inspect the backflow preventer and test cocks before pressurizing. (2) Open the main supply valve slowly (1/4 turn at a time, waiting 30 seconds between turns) to gradually fill the mainline and prevent water hammer. (3) Activate each zone from the controller, inspecting every head for: proper rotation/spray pattern, correct arc and radius, leaks at heads and fittings, and heads that have settled below grade. (4) Check the backflow preventer for leaks. (5) Verify rain sensor operation. (6) Program the controller for spring scheduling. (7) Document any repairs needed. (8) Arrange for annual backflow assembly testing. This methodical approach catches problems before they cause water waste or landscape damage.

Question 3: A zone valve is stuck open (water continues flowing even when the controller turns off the zone). What should the technician check first?

The rain sensor
The solenoid, diaphragm, and bleed port for debris or damage (Correct answer)
The water meter for accuracy
The controller's transformer

Correct answer: The solenoid, diaphragm, and bleed port for debris or damage

A valve stuck open is typically caused by debris in the diaphragm or bleed port, a torn diaphragm, or a solenoid that isn't seating properly. These components control the valve's closing mechanism and are the first items to inspect.

Globe-pattern irrigation valves close when water pressure fills the chamber above the diaphragm, pushing it down onto the seat. If the valve stays open: (1) Check the solenoid — is it de-energized? (If stuck energized, the controller or wiring may be at fault.) Manually turn the solenoid clockwise to ensure it's fully seated. (2) Remove the solenoid and inspect the bleed port — a tiny piece of debris can hold it open. (3) Remove the bonnet and inspect the diaphragm — look for tears, holes, or debris on the seat. (4) Check the spring (if equipped) that assists closing. (5) Inspect the valve body seat for damage or erosion. Most stuck-open valves are resolved by cleaning the bleed port or replacing the diaphragm — a 5-minute, $5 repair versus replacing the entire valve.

Question 4: What is the correct method for winterizing an irrigation system by compressed air blowout?

Use the highest pressure air compressor available to ensure all water is removed
Connect a compressor (limited to 50 PSI for PE/PVC) to the mainline after the backflow preventer and blow out each zone sequentially, starting from the farthest zone (Correct answer)
Only blow out the mainline and leave water in the laterals
Turn off the water and let the system freeze naturally

Correct answer: Connect a compressor (limited to 50 PSI for PE/PVC) to the mainline after the backflow preventer and blow out each zone sequentially, starting from the farthest zone

Winterization by blowout uses compressed air to push water from all pipes, valves, and heads. Air pressure must be limited (50 PSI for PE/PVC, 80 PSI for copper) to prevent pipe and fitting damage. Each zone is blown out individually until no water is visible from the heads.

Proper blowout procedure: (1) Turn off the water supply and relieve pressure. (2) Connect the compressor downstream of the backflow preventer (air through the backflow can damage its internal components). (3) Set the regulator to 50 PSI maximum for PVC/PE systems (80 PSI for copper). (4) Open one zone at a time on the controller. (5) Allow air to push water through the heads for 2-3 minutes per zone — until a fine mist replaces the water stream. (6) Do NOT run air through a dry zone (no water) — friction heat can damage PVC and head seals. (7) Repeat for all zones, then blow the mainline. (8) Open test cocks on the backflow preventer. (9) Drain the backflow preventer. Compressor volume (CFM) is more important than pressure — a minimum of 20-80 CFM depending on zone flow rate.

Question 5: A rotor sprinkler head is turning but the radius has decreased significantly from its original design. The most likely cause is:

The controller's programming changed
Low water pressure, a worn or clogged nozzle, or debris in the filter screen (Correct answer)
The head is installed too deep
The common wire is broken

Correct answer: Low water pressure, a worn or clogged nozzle, or debris in the filter screen

Reduced throw radius in a rotor is typically caused by low operating pressure (often from a system leak elsewhere), a nozzle that has worn to a larger orifice (reducing pressure), a clogged nozzle, or a dirty filter screen restricting flow to the head.

Troubleshooting reduced rotor radius: (1) Check the operating pressure at the head using a pitot gauge — compare to the manufacturer's specification (typically 45 PSI for residential rotors). (2) If pressure is low, check for leaks on the zone (look for wet spots, run the zone and check the water meter). (3) Remove and inspect the nozzle — worn nozzles become larger, allowing more flow at lower pressure, reducing the throw. (4) Check the inlet screen/filter — remove and clean or replace. (5) Verify the correct nozzle is installed (compare to the nozzle chart). (6) If pressure is adequate and the nozzle is clean, the drive mechanism may be worn, causing poor stream formation. Addressing the root cause (often a leak elsewhere on the zone causing pressure loss) is essential.

Question 6: When replacing a broken sprinkler head, the technician notices the replacement head sits 2 inches above grade after installation. The correct action is to:

Leave it as installed — it will settle over time
Cut and lower the swing joint or riser to bring the top of the head flush with grade (Correct answer)
Mound soil around the head to match
Install a taller head to make it more visible

Correct answer: Cut and lower the swing joint or riser to bring the top of the head flush with grade

Sprinkler heads must be installed flush with the surrounding grade. A head sitting above grade is vulnerable to mower damage, is a trip hazard, and looks unprofessional. The technician should adjust the swing joint depth or cut the riser to bring the head to the correct level.

Proper head height is critical: (1) The top of the head body should be flush with the surrounding grade. (2) For turf applications, the head can be set 1/4 inch below grade — settling will bring it level. (3) Heads too high are struck by mowers (breaking the head and potentially the lateral connection), create trip hazards, and are aesthetically unpleasing. (4) Heads too low get buried by thatch and soil accumulation, reducing pop-up clearance and spray performance. (5) To adjust, dig around the head, shorten or lengthen the swing joint, and re-compact soil around the body. (6) Using a head-height gauge tool ensures consistent installation across the site. On settling or newly graded soil, plan to revisit and adjust head heights after 6-12 months.

CIT - Certified Irrigation Technician System Maintenance and Repair 2

A sprinkler head is not retracting fully after the zone turns off.
The most likely cause is: