Help, automatic sprinkler valve not working correctly

[pron22]

I recently installed an irrigation system in my backyard. 3/4 zones I added work perfectly when connected to the automatic controller. The fourth has me banging my head against a wall...

-Using the manual bleed, all the sprinklers in the zone pop-up great and perform as expected
-Using the manual knob of the solenoid, again, the sprinklers in the zone work great
-When I connect the solenoid wires to the controller and turn that zone on, only a few of the sprinklers pop-up and the ones that do only sort of pulse water. Also, there is a knocking sound at the valve.

I have verified the voltage at the valve is ~26V and I can hear the solenoid click on and off so I'm pretty sure the solenoid is good (also it's brand new).

At this point, I suspect it is a flow or pressure problem but I don't quite understand how it can still work manually but not by electrically activating the solenoid.

Any help would be greatly appreciated...

[Fireguy97]

Just because the solenoid is new doesn't mean that it's good. I would look at making sure that the common and power wires are twisted properly in the valve box and that the wires are set in the clock properly.

The plunger in the solenoid could be sticking. You will hear a click, but the plunger won't move.

If that doesn't work try swapping out the solenoid with a solenoid that is known to be good from another valve.

Are there at least two valves in the valve box? If there is and it's still not working at this point, try swapping wires to eliminate a wire problem.

A flow or pressure problem will also show up when you manually turn the valves on from the box. It's some kind of electrical problem.

Mick

[hj]

A defective diaphragm in the valve will NOT let it open all the way, and WILL cause a chattering sound. The solenoid only bleeds off enough water to let the valve open properly and a bad diaphragm changes the dynamics. The manual opener vents a lot more water which would overcome the defective diaphragm, which is why that gives full flow. Either repair the valve or replace it.

[BRD]

If you have juice to the valve then,As suggested, either the solenoid is stuck closed, diaphragm is bad, and not opening up all the way or you may have a partially clogged exhaust port, which is located directly under the solenoid plunger. You can check it by removing the solenoid then slip a 18 guage strand of wire through that tiny hole to make sure it is open. If that hole is clogged or partially blocked the valve will not open. Don't forget to shut the water off first.Irrigation valves are electrically activated , but hydraulically operated.

[greenbaypackersfan]

wow, been reading through most of the threads here on the Irrigation/Sprinkler System part of the forum. I would say Fireguy97 offers some good information and solid tips. I wasn't going to post this since I did not contribute anything to this thread but just want to point out, everything he has pointed out on my part of sprinkler set up worked perfectly.

thanks again !