Question
QUESTION: Hello Tony,
I have drip watering for my raised bed garden; using Orbit
brand anti siphon valves (4) on a rainbird timer. When the timer activates the valve goes on for a few minutes, then off and repeats this during the whole time period. It is happening with all four valves(not at the same time) to my knowledge. i turned the flow control to the halfway point and has made no difference. three of the valves have 20 psi pressure reducers on the output side of valves at the raised bed.  the valves are remote from the garden and I believe they are 4- 6" higher than the risers for the drip tubes. Any ideas?

Thanks, Pat

ANSWER: Hi Pat

First thing, your pressure reducers should be installed upstream (before) the ASV.  Too much pressure on the diaphragm and ASV will cause erratic performance.

Can you tell me what happens when you turn on each valve manually without using the controller?  One at a time.

Also let me know if the ASVs dump water out of the top during operation.  Your valves must be a minimum of 6" above the highest emitter.

Thanks
Tony

---------- FOLLOW-UP ----------

QUESTION: Tony,
When I turn the valve on manually; it works fine on each one. the ASV does not dump water during operation.
one zone emitters(on wine barrels) are probably not at least 6" lower than the valve.

Answer
Hi Pat

If the valves operate uninterrupted when you open them manually, then there is likely an electrical issue.

Valves typically require voltage minimums to operate and remain open.  The first thing to troubleshoot in this case is the controller.  Where the valve wires connect to the terminal strip on the controller, use a volt meter to monitor the line voltage when the zone is supposed to be on.  Put the black probe on the Common terminal and the red one on Zone terminal after you manually turn on the zone from the controller.  It should read between 24VAC and 27VAC.

If the voltage does not vary beyond the range noted above, you may want to ring out the wires and check the continuity from the controller to the valve(s).  Set the multimeter to the ohm setting. The symbol for ohm is the Greek letter omega. If there is more than one ohm setting, choose X1.  A digital meter performs the test providing a numeric reading.  

Note that while the probes are not touching anything, the multimeter will indicate a reading of infinity. A reading of infinity means that the circuit is open. When you touch the two probes together, the reading changes to zero. A reading of zero indicates that the circuit is closed or complete. A complete circuit is one that can conduct electricity; an open circuit cannot.  Place the black probe on the common wire and the red one on the suspect valve wire.  Check the resistance of the problem circuit. If the system has valves that typically measure about 30 ohms of resistance, and the ones in question measures 6 to 8 ohms, suspect a short circuit. To verify this, go to the valve box and disconnect the field wires from the valve. Check the resistance directly at the valve. Confirm whether the short is in the solenoid. If so, replace the solenoid. If not, it's time to look closer at the field wiring.  

Return to the controller and check the resistance through the circuit - remove the wires from the controller (noting which ones are which). With the solenoid removed from the loop and the controller, the resistance reading through only the field wiring is probably just a couple of ohms. If the resistance measures more than this, the issue lies in the wiring, not the solenoid.

Hope this helps.

Tony