CIT - Certified Irrigation Technician System Maintenance and Repair Questions and Answers — Questions and Answers
Question 1: A technician performing a spring start-up on an irrigation system that has been properly winterized should perform which of the following steps FIRST to prevent system damage?
- Turn on the controller and manually activate each zone to check for broken heads.
- Open the main shut-off valve quickly to flush debris from the mainline.
- Ensure all drain valves are closed and then open the main shut-off valve very slowly. (Correct answer)
- Open the test cocks on the backflow prevention device before turning on the water.
Correct answer: Ensure all drain valves are closed and then open the main shut-off valve very slowly.
The most critical first step when reintroducing water is to open the main valve slowly. This allows the pipes to fill gradually, preventing a sudden pressure surge known as water hammer, which can crack pipes, fittings, and other components. [3, 10]
Question 2: A pop-up spray head in a turf area fails to retract fully after the zone shuts off, creating a potential hazard. What is the most common reason for this issue?
- The system pressure is too low for proper operation.
- The retraction spring inside the sprinkler body is broken.
- The nozzle is clogged with mineral deposits.
- Debris is wedged between the riser stem and the wiper seal or sprinkler body. (Correct answer)
Correct answer: Debris is wedged between the riser stem and the wiper seal or sprinkler body.
The most frequent cause for a pop-up sprinkler failing to retract is debris, such as sand, dirt, or grass clippings, becoming lodged between the movable riser and the stationary body or wiper seal. This friction prevents the retraction spring from pulling the riser down. [16, 21]
Question 3: A client reports an unusually high water bill. With all water off in the house and the irrigation controller off, a technician observes the small leak indicator dial on the water meter is spinning slowly. This indicates a leak in which part of the system?
- A cracked lateral line after a zone valve.
- The mainline between the water meter and the zone valves. (Correct answer)
- A broken sprinkler head in the lowest zone.
- A weeping diaphragm in a zone valve.
Correct answer: The mainline between the water meter and the zone valves.
The mainline, the section of pipe between the water meter and the zone valves, is always under pressure. If the leak indicator on the meter moves when all fixtures and the irrigation system are turned off, it confirms a constant leak in this continuously pressurized section of pipe. [17, 18, 26]
Question 4: After a zone turns off, the sprinkler heads continue to weep or dribble a small but constant amount of water. The valve box itself is dry. What is the most likely cause of this problem?
- A small piece of debris is preventing the valve's diaphragm from sealing completely. (Correct answer)
- The controller is sending a low, residual voltage to the solenoid.
- The solenoid coil has failed and is stuck partially open.
- The mainline pressure is too high, forcing water past the valve seal.
Correct answer: A small piece of debris is preventing the valve's diaphragm from sealing completely.
A constant weep or leak through the heads when a zone is off is typically caused by a small particle of dirt, sand, or PVC shaving caught between the diaphragm and the valve seat. This prevents the diaphragm from creating a complete, watertight seal, allowing water to pass through. [27, 37, 39]
Question 5: When winterizing an irrigation system with PVC piping using an air compressor, what is the generally accepted maximum air pressure (PSI) to use to avoid damaging components?
- 25-35 PSI
- 100-110 PSI
- 40-80 PSI (Correct answer)
- 90-100 PSI
Correct answer: 40-80 PSI
Most industry guidelines recommend keeping the air pressure between 40 and 80 PSI for systems with rigid PVC pipes. Pressures exceeding 80 PSI can crack PVC fittings, damage valve internals, or break sprinkler heads. For polyethylene (poly) pipe, the maximum pressure should be even lower, around 50 PSI. [19, 20, 23]
Question 6: What is the most critical routine maintenance task for a drip irrigation system to prevent emitter clogging and ensure uniform water delivery over time?
- Burying the tubing deeper into the soil annually.
- Checking the controller's battery backup every month.
- Regularly opening the end caps or flush valves to flush the laterals. (Correct answer)
- Increasing system pressure at the beginning of each season.
Correct answer: Regularly opening the end caps or flush valves to flush the laterals.
Over time, fine sediment, algae, and mineral deposits can accumulate inside drip tubing. Regularly flushing the lateral lines by opening the end caps or flush valves and running water through them is the most effective way to clear out this debris before it can clog the small orifices of the emitters. [5, 13, 14]
CIT - Certified Irrigation Technician System Maintenance and Repair Questions and Answers
A technician performing a spring start-up on an irrigation system that has been properly winterized should perform which of the following steps FIRST to prevent system damage?