TSB05062015: Performance Programming Under Mandatory Restrictions

With the drought deepening in California, the popularity and demand for SmartLine controllers grow. The Technical Support team has issued this Technical Support Bulletin to convey to our customers programming and run time examples for a better understanding of SmartLine performance expectations.

Please follow the instructions below. The information contained is a representative example of SmartLine

• This is a typical Southern California forecast for the zip code: 90210. Here’s an example of the temperature data downloaded to a SmartLink controller.

• Provided the forecast for zip code 90210 above, you can see the accrued daily watering need (in run time minutes) for each zone. Take, for example, Zone 2.  It has Rotors, Warm Season Turf, and no Slope Factor.  By the end of the week, its’ combined irrigation need (or run time in minutes) is one hour and 30 minutes.

• Imagine you’re faced with new watering restrictions and outdoor irrigation is limited to a twice-per-week watering window (Tuesdays and Saturdays ONLY) and there’s a no watering window from 9AM-4PM.

Here’s how the daily run times for each zone above would translate in SmartLink on a twice-per-week watering schedule.

• SmartLink’s Run/Soak makes adjustments to sprinklers cycle time in order to match the intake rate of the soil. This automated calculation reduces or eliminates run off water.  The overall benefit is greater system efficiency, which means more water is available to the plant.

Below is an example of how Tuesday’s SmartLink Run/Soak breaks down accrued run times to match that soil’s intake rate.

• Minimum deficits and excessive deficits are terms that are relevant to the operation of SmartLine and are defined here:

1. A Minimum Deficit is the deficit value a SmartLine controller must accumulate before watering can occur. This is to prevent watering times that are so short that they are ineffectual. The factory setting for minimum deficit is 0.15”. In the circumstance that a watering program is scheduled to run, any zone that has not accumulated this minimum deficit value will NOT irrigate.
2. An Excessive Deficit is an alert that occurs if the deficit value on any given zone has exceeded 1½”. This alert is self-clearing; once irrigation occurs for a length of time sufficient to reduce this deficit or a rain event occurs.

The excessive deficit alert may occur on higher station count zones resulting from water windows being narrow enough to prevent the later cycles from occurring in their entirety.  It is misunderstood that these zones did not receive any irrigation.  Using the clay soil type as in the example above can mitigate this.  This will allow irrigation to occur on the higher count zones before cycling back through. And while this alert may still occur permanent wilt point may be able to be avoided.