Quote:
Originally Posted by Arctic Fox
With all of the rain in the area, I currently have my garden irrigation turned off.
Yesterday there was a very brief power cut - less than a second - and I heard the irrigation start up (zone 2).
I assume that the timer works by sending a pulse of electricity to a solenoid which opens the valve, then a second pulse to close it at the end of the allotted time, but how would a power cut (and maybe a small power surge when coming back on) do the same when the timer is in the OFF position?
I ask because, not being here full time, I don't want my irrigation to be triggered by a power cut (or lightning, as has happened once before) while I am absent.
Thank you
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I am a retired control system engineer with 40 years of experience. My home in The
Villages was built 16 years ago and it has a Hunter sprinkler control box mounted inside the garage. In the bottom part of this box there is a 9-volt battery that provides power to the controller when the 115 V power feed to the box is disrupted; as a minimum that battery keeps the electronic time-of-day clock running inside the box. Until I read your post, I had forgotten about this battery, and today I replace my battery. Homeowners, who will be out-of-town for long periods of time, should make sure that the backup battery in their sprinkler controllers is not several years old. (Some newer versions of sprinkler controllers may not have backup batteries.)
The control box sends power to individual solenoid valves to turn on the water to each zone. I am 99.99% sure that the solenoid valves are not-pulse on pulse-off; while the 115 V power to the system is lost, all the solenoid valves would be off.
If the backup battery in your control box was dead when you lost 115 V power for one second that might be the cause of the erratic operation of your system when power was restored.