How to use the "Deactivate on Precipitation" option

[Jim]

Would you like your irrigation to stop if it is currently raining or if rain has been detected within your area?   Most people would, if it could be done automatically.

By checking the "Deactivate on Precipitation" option when defining or editing your irrigation cycles you can do this.

If you check the "Deactivate on Precipitation" option, then when the cycle is about to start, LawnCheck gets the current local weather information and checks the current code for precipitation.  If the code provided contains precipitation, the cycle will be blocked.  The block will be noted in the log.

If you live in a microclimate where your precipitation does not generally meet that provided by the zip code code weather forecast, you might want to install a local rain sensor directly to your controller.  You could also experiment with changing the zip code you use to one that provides closer estimates of your weather.

[ihstiv]

Hi Jim,
I noticed that my cycle wasn't blocked yesterday or today even though it rained. The weather report yesterday for my zip code indicated a forecast for 'light rain'.

Could you elaborate on what you mean by 'the current code for precipitation' ?

I'm using this map to try to find a zip code that is closer to my micro climate:
http://www.usnaviguide.com/zip.htm

I have the rain brain - just haven't had a chance to hook it up yet.

Is there a way to tell the controller not to run if it rained yesterday - even if no rain is forecasted for today?

Thanks!

[Jim]

HI ihstiv,

Thanks for your question.

When you select the "Deactivate on Precipitation" option, Lawncheck checks the current condition code weather code for your zip before sending the irrigation command.  If the current condition code at that time does not indicate any type of precipitation, the irrigation command goes through.    There are times around San Jose when it will rain from 5am to 6am and then abruptly stop raining, and the Yahoo weather condition code for the zip will change to "cloudy."  If a command was scheduled to be delivered when the condition code was cloudy, it would miss the fact that it rained.  

LawnCheck doesn't monitor condition codes for your zip code on a 24 hour basis.  This might be an interesting upgrade, because then it might provide better irrigation information, but for now, only at the time the irrigation command is sent.

In the meantime, the best way to block during and after rain is a local rain sensor with rain brain turned on.    The combination a local sensor with rain brain, and Yahoo weather is even better.  My report log shows cycles stopped by Yahoo weather before it rains at my location because I use a zip code that is to the west of my actual location, and most rain comes in from the west in this area.

Hope this explains,

Jim

[ihstiv]

Hi Jim,
Thanks for the detailed explanation - makes sense and good to know.

I agree that expanding the weather service data would be a nice upgrade, here are a couple wish-list ideas:

1. check actual rainfall data w/in user defined number of hours in the past by (nearest) zip.

2. add option to choose how many hours in to check for actual rainfall data in the past, and choice to block irrigation cycles for user defined number of days if precipitation exceeds user defined amount.

3. add option to choose how many hours in the future to look ahead for precipitation in local forecast with option to block cycles for user defined number of days.

I guess you would need some sort of API that interacts with site like this: http://water.weather.gov/precip/

Fun stuff.

Thanks again.

[Jim]

Hi ihstiv,

There is a lot of work to do for sure.  Thanks for the link.  Looks like a wealth of data, and looks like weather by latitude/longitude, though also they seem to have zip code translation built in.  I'll be checking out that site.  Thanks for posting it.

Jim