Why Does My System Keep Coming On?
You programmed your controller to start watering at 5am. Let’s say you have five zones and they water ten minutes each. The cycle should be finished by 5:50, right? So why are the zones still watering at 8:30?
What most likely happened is you confused program start times with zone run times. This mistake is common, and understable, because the language is counter to intuition. Don’t feel dumb, the industry is slow to correct user unfriendliness the more they advance the features. It’s too bad Steve Jobs didn’t live long enough to create an irrigation controller.
Most newer controllers have a feature called “stacking” which will run programs consecutively in their entirety in case start times are overlapped. I will explain this further after we go over the difference between ‘start time’ and ‘run time’. ‘Start Time’ refers to the time of day you want the ‘Program’ to begin. In the example we’re using the start time is 5am. A ‘program’ is the consecutive zones chosen to water for the duration set for each. Most controllers will have options for Program A,B,C, etc. We are sticking with the default Program A, and we’re not going to clutter our minds with those other options- we’ll talk about them later. So we have zones 1-5 all assigned to Program A, and Pgm A is set to come on at 5am. That means the program starts at 5am and each zone waters consecutively .
Run Time refers to the length of time each zone waters, i.e. zone 1=10m, 2=15m, 3=7m, etc.
Now, here’s where some people make the Big Mistake. Since a lot of controllers have more options than any user needs, the Start Times setting will display “Start Time 1, Start Time 2, Start Time 3..” This will lead folks to think, “Oh, I have to assign a start time for #1, 5:00, and that is going to run for 10 minutes so I better program Start Time 2 for 5:10, that’s going to run for 15 minutes so I program Start Time 3 for 5:25 …” and so on. What happens next is your water bill increases 500%. Start time 1 is all you need. All 5 zones water one after the other with just one start time. If you program 5 different start times, the controller is going to water the whole program 5 times.
You may ask, “Wouldn’t the controller get confused if a program was already running at the time another start time was programmed?” That’s where ‘stacking’ comes in. The controller will start the next program as soon as the first one is finished., and any others programmed. So in our very first example the system would water a total of 4 hrs 40 min. instead of 50 min.
I think stacking is STUPID. Name brand controller brochures boast about this feature. I’d prefer them to have an error message appear the moment the user adds a conflicting start time. Then they would be forced to rethink, or call a sprinkler guy to explain what’s going wrong, and avoid a big water bill. I can’t think of any reason a controller should have more than 3 start times anyway.
Multiple start times are appropriate in a handful of scenarios. Pots and hanging baskets need a little bit of water more than once a day. If you water too long, water just runs out of the bottom. So you water a short time, a few times a day, every day. New grass seed needs short watering times, more often. You want it to stay wet but avoid run-off. The same thing applies to steep slopes.
There is a far better feature for these situations called ‘Cycle And Soak’. I know the Weathermatic Smartline (The controller we currently use in all new installations) has it, as well as the Hunter Pro-C, and Rainbird ESP-LX to name three. This feature allows you to program a length of time to water, and length of time to wait. Say your new grass seed needs 30min. of water a day, but it starts puddling after 10min. Say it takes 20 min. to dry out sufficiently. You program the zone for 30m, set the Cycle/Soak for 10/20 and the zone will run for ten minutes, wait 20, water 10, wait 20, then finish watering the last 10. A much better solution in my opinion.
What about those different programs I mentioned earlier? Oh yeah, Program A, B, C etc. Another avenue to confusion. The only reason to have a separate program is to divide a zone or zones into different schedules. Say you have some lawn and shrub zones that only need watered once a week, but a drip zone to your pots you need to water every day, twice a day. Then you would program start time, run time, and days to water for all shrub and lawn zones while set to A, then switch to B and program start, run, and days for the drip zone. Then you have C and or D for whatever other crazy thing you need, say a pond fill line that only needs to run once a month.
Good luck sprinkler cadets! I’d love to get emails from anyone left more confused after having squandered five minutes reading this post. firstname.lastname@example.org