[Cloud9...68]

I figure any group talented enough to keep a bunch of 16-to-19 year-old German GT's running in fine form would have no trouble figuring out something as mundane as a lawn sprinkler, so here are my symptoms: Zone 4 of my nine-zoner automatic sprinkler system is simply not turning on when it gets its signal to do so from the control box. All of the other eight zones work perfectly. If I go into the valve box and open up the bleed screw a little (to the point that some water is seeping out around it), it starts working. I can feel the valve shuddering as I open the bleed screw, as though it's struggling to open. But when I then gradually screw it back down by hand to stop the seeping, the sprinklers for Zone 4 stop working.



I've replaced the solenoid and the diaphragm of the Zone 4 valve, and this didn't help. I've also swapped the wiring in the control box between Zone 4 and Zone 5, and Zone 5 still works perfectly, and Zone 4 still doesn't. The system is 16 years old, but as I said, all the other zones work perfectly, the pressure is perfect, etc. Any ideas as to what's up with Zone 4? There isn't a whole lot left to replace. Thanks.

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[Cloud9...68]

OK, I've boiled it down to a very basic problem - Zone 4 ONLY works when I open the bleed screw in its valve. It doesn't come on when the controller is supposed to trigger it to, and it doesn't turn off unless I close the bleed screw. In other words, it only works in manual mode, as a result of my opening the bleed screw, and only shuts off when I close the bleed screw.



So, the new solenoid I bought could be bad, or some other component of the valve, other than the diaphragm, could also be bad. Any ideas are welcome, but at least for now, I have a work-around, in that I can run it in manual mode.

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[craigawoodman]

Cloud,



Did you check the voltage being applied to the solenoid? You could have too much resistance back to the controller for that circuit (i.e. the wire or insulation has worn through). You might have to "bell" out each circuit to check the circuit resistance to see if it is getting the voltage, bu not enough current to pick up the solenoid.



If not, the valve is stuffed (could the plunger be getting stuck for some reason). Therefore you would need to replace the entire valve - not just the solenoid.



Other issue, could be junk in the valve blocking it - but then it would normally leak.

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[Cloud9...68]

Craig,



Thanks for the response. No, I didn't actually check the voltage being applied to the solenoid, but I did swap the wires at the control box going to the bad zone (4) and a working zone (5), and zone 5 still worked, and 4 still didn't, so I assume the voltage coming from the controller to the valve box is OK. I should measure it, though.



Yes, it's highly likely the valve itself could be bad. It's strange, though, that it seems to be moving freely, and it's very clean inside as well.

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[flash]

i am continually replacing valves - on average i replace at least 1 a year - i don't buy the cheap ones either

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[Cloud9...68]

Yeah, I've found that what some man once said about women is even more true for sprinkler systems: "Can't live with 'em, can't live without 'em." Once your system gets over about 10 years old, you really have to check each head very frequently by turning each zone on for a couple minutes at a time. I've found two "gushers" already this year. This procedure is very time-consuming, but if you don't check your entire system, you run the risk of wasting a ton of water, and not finding out about it for a long time (like when the next bill comes).



As far as valves, I've been pretty lucky so far - this is my first zone valve so far that looks like it's given up its ghost. But I'm sure many more are to follow.

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[craigawoodman]

Cloud,



It is not just the voltage between the terminals, but the resistance from the box to the solenoid and back. If you put a 1Mohm resister in there - you will still read 12V across the terminals, but very little current. Same as testing open circuit voltage - it shows what is getting to that point in terms of potential but not current. Bit like when you turn the hose off at the tap, but there is still pressure in the hose, but no flow.



Let us know how you get on. If you swapped activiting points on the controller - it is not the controller - it is either the wiring or the solenoid/valve itself.



Craig

Sorry - you could check the valve versus wiring by removing the valve/solenoid and taking it to the controller to see if it actuates with shorter wiring. If it does - then most likely it is a wiring issue. Same if you have a spare solenoid/valve - check it at the controller and then with the wiring at the installed position.

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[Cloud9...68]

Thanks, Craig, I'll give that a try, as I do have a spare solenoid (the old one that I thought was bad, but now suspect that it's OK).

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[craigawoodman]

Cloud,



If you have a multi-meter. Join the wires together at the controller (off the controller) and then measure the resistance at the solenoid between the two open ends of the wiring. It should be very low (almost zero) for a good circuit. You could do the same for a circuit next to the one not working to see what the corresponding difference is.



Craig

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