Valves turn on as programmed, but never close down

lakesregionscapes

LawnSite Member
Location
Tuftonboro,NH
Over the 25+ year in the landscaping industry we've learned the basics of irrigation - but this one has repeatedly tested the limits of our patience.
In the current inexistent local labor market we cannot get anyone to get back to us; we're all just treading water with our current customers, plus the big local irrigation guy retired last year. Hoping you can help.

This years' headache began about a week after startup; the customer found all zones open and running for over 4 hours.... As in zone 1 starts, then 15 minutes later zone 2 starts, 15 minutes and zone 3 starts, and 25 minutes later 4 goes off; all the while not one shuts back down. The only way to get it to stop is to unplug the pump. It resets after a while, and you can get it to repeat the screw up on manual run. (But "test all zones" at 2 minutes each doesn't do it!)
System is a Rainbird controller, 4 zones, submersible pump in the lake with small pressure tank. Installed by a local established irrigation guy some 6-7 years ago.
Started up as usual: bled the valves, tested the zones, replaced a head or two, all fine. Issue started a week or so later.
Cleaned the valves, checked all the wires (good), did a factory reset and reprogrammed the controller, tested again... all good.
Called back two days later - ran for 4 hours until unplugged.
Since the consensus was it seemed unlikely that all 4 valves would screw up at the same time, in the same way, we tried replacing the controller... no dice. We did discover that even unplugging the controller won't stop it - definitely not the controller.
Before we replace all four valves (and give the homeowner a salty bill) are we overlooking something? we really don't have time to go pick up and replace these only to discover it still isn't working... Already have way to many balls in the air.

Any suggestions and input are most appreciated.
 

1idejim

LawnSite Fanatic
“Called back two days later - ran for 4 hours until unplugged”

We did discover that even unplugging the controller won't stop it”

The above statements contradict one another.

One suggests electrical while the other suggests hydraulic.
 
“Called back two days later - ran for 4 hours until unplugged”

We did discover that even unplugging the controller won't stop it”

The above statements contradict one another.

One suggests electrical while the other suggests hydraulic.
I think he meant unplug the pump. He mentioned unplugging the pump which would reduce/eliminate the pressure. This sounds hydraulic to me. It is a head scratcher though.
Is there a lot of back pressure on all these zones?
 

1idejim

LawnSite Fanatic
I think he meant unplug the pump. He mentioned unplugging the pump which would reduce/eliminate the pressure. This sounds hydraulic to me. It is a head scratcher though.
Is there a lot of back pressure on all these zones?
OK now that you’ve mentioned that, I have to wonder what’s different now than when the system was working correctly?

what’s changed?

Has anything changed?
 
OP
L

lakesregionscapes

LawnSite Member
Location
Tuftonboro,NH
Yes - customer was unplugging the pump. It is more accessible than the controller which is tucked under a set of stairs (and in the middle of an ant nest - fun times).
Pump puts out a lot of pressure - it has to push up a pretty good hill, so they got a stronger one.
Come to think of it, some of the original whirllybird heads were switched to Hunter rotors because they clog too easily on lake water.... could this have altered the pressure dynamics? The back pressure from the system should be less since output increased... but that would be better, since I remember hearing the installers argue about too much pressure from the pump?
 
OP
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lakesregionscapes

LawnSite Member
Location
Tuftonboro,NH
I'll add there was no indication of a significant difference of pressure watching the heads run... roughly the same coverage except for a couple still gummed up from earlier.

Pump in lake is a 3 wire well pump, removed for storage by cutting wires (not my idea). Could reconnecting wrong wires allow operation at a different rate? I'd think either it would work, or it wouldn't.
 

Delmarva Keith

LawnSite Senior Member
Adding my 2c, thinking about how valves work, is it possible they’re not getting enough pressure to close? Or too much pressure so there’s not enough differential downstream when it’s time to close. Can you try these two tests: 1. run a zone for say 15 min and watch dynamic pressures; switch to the next zone, what happens (both in operation and pressures)? 2. (Assuming your controller can do it) program a delay of a few minutes between zones, or just do that manually; any change in operation or pressures?
 

RhettMan

LawnSite Gold Member
Location
Texas
Boots' subtle maxxed open flow control suggestion could be some sort of "off while pressurized until turned on the first time" kind of thing...
 
OP
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lakesregionscapes

LawnSite Member
Location
Tuftonboro,NH
We'll have to try the manual version of the break between zones: the controller is pretty basic. This would replicate the cycle we were running while adjusting the heads. The valve box and controller are two long flights of stairs below the zones and on the wrong side of the house from two of them... there's a lot of jogging up a down, and yelling " how "bout now?". The entire place is quite steep - a lot of pressure while the lines drain after valves close - if they close.
Another observation we made was that the drip line started spitting as soon as pump was plugged back in, i.e. zone 4 valve never closed, even after a longish rest.
Should be back there tomorrow. 90s coming in next Monday. That lawn will fry without water....
 

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