- Certified Irrigation Technician Controllers and Programming Flashcards

A client wants to water their lawn at 6:00 AM but the system has 4 zones that cannot run simultaneously due to insufficient water supply. The controller should be programmed to:

Answer: Stack zones sequentially on the same program with a 6:00 AM start time

When zones cannot run simultaneously, they should be stacked sequentially on the same program with a single start time. The controller will automatically run each zone in sequence after the previous one completes, starting at the programmed time.

What is the purpose of a 'rain delay' feature on an irrigation controller?

Answer: Suspends irrigation for a user-selected number of days, then automatically resumes normal scheduling

The rain delay feature temporarily suspends all programmed irrigation for a specified number of days (typically 1-7 days) after a rain event. After the delay period expires, the controller automatically resumes its normal watering schedule without reprogramming.

A controller is described as having 'non-volatile memory.' This means:

Answer: Programming is retained even if power is lost

Non-volatile memory retains all programmed schedules, station run times, and settings even during power outages. When power is restored, the controller resumes normal operation without reprogramming.

A smart controller uses evapotranspiration (ET) data to adjust irrigation schedules. ET-based controllers primarily calculate water needs based on:

Answer: Weather parameters including temperature, humidity, wind, and solar radiation

ET-based smart controllers use weather parameters — temperature, humidity, wind speed, and solar radiation — to calculate the evapotranspiration rate and adjust irrigation run times accordingly. This allows the controller to apply only the amount of water the landscape has lost.

When programming a controller for cycle and soak, what is the primary purpose of the soak time between cycles?

Answer: To allow water to infiltrate into the soil and prevent runoff

Cycle and soak divides a zone's total run time into shorter cycles with soak periods between them. The soak time allows water to infiltrate into the soil, particularly on slopes or clay soils, preventing surface runoff and improving irrigation efficiency.

A two-wire decoder irrigation control system differs from a conventional multi-wire system in that it:

Answer: Uses only two wires to communicate with and power all field decoders and valves

A two-wire decoder system uses a single pair of wires (plus a ground) to communicate with and power all field-mounted decoders. Each decoder has a unique address and activates its associated valve when signaled by the controller, greatly reducing wiring requirements.