When the RD600, 900 or 1200 timer is turning on a valve when you’re not expecting it to be in. it usually is due to some unexpected programming.  Sometimes this happens by having switches in the wrong position when programming is being added and you end up with another schedule running that shouldn’t be.  Here are some troubleshooting tips you can follow;

1. Let the sprinkler timer tell you what it’d doing.  Ensure the Rain Dial’s bottom center switch is in the run/manual position. When the valve/station is on when it  should  not be, set the dial to that station number (the station number will appear as a small number in the top row of the display).  When the dial is on that station number, look at the display.  The display will show you a letter followed by the remaining run time for that station, e.g., B:05.   The letter indicates which schedule is currently running.  Most people find that this schedule is not something they intentionally programmed into the Rain Dial.  Assuming you don’t want this schedule, remove it by
   1. placing the bottom center switch to set-programs, the schedule switch to the letter indicated (A,B or C), and
   2. modify the schedule as needed (change the days, start-times, runtimes etc.)
   3. If you don’t want that schedule to run at all, set the start times to OFF, or days of  the week to OFF, or run-times to off.  I usually set all of them to off in case I accidentally change one of  them by mistake.  This will ensure that just one mistake doesn’t cause the schedule to run.
2. If you can’t find any programming  issues, follow the instructions on the DIY Troubleshooting page to reset the timer back to factory defaults, then reprogram it.   This usually clears up any programming issues.
3. Wiring issues can cause valves to run at the same time, if you’ve modified wiring recently, double check  them.
4. Make sure the station number you want to run is the right one –  sometimes people think that one station is  the front yard, when it’s actually the front and back yard, or just the back yard.
5. Sometimes in rare cases, one valve going on can trigger another one to go on because of the water pressure change. This is rare, and likely due to a ‘weak’ diaphragm in the valve that should be replaced..

We’ve put this information together on this page to help people with their  Irritrol RainDial timers.  If it’s been helpful, please help us by making a reasonable donation.  The information on this site often helps people avoid hiring a landscaper come out and ‘help’ and sometimes they recommend replacing parts that don’t need replacing.  We’ve done this to help you not be dependent on other people.

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