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corker

Senior Member

Posts: 15

Location: Satellite Beach, FL

21

Tuesday, May 17th 2016, 11:04am

OK, New Problem now...

Installed the new Toro hydraulic valve and I thought all was well. The small diameter plastic hose goes into a nipple on the bonnet of the new valve that has a very small orifice. Now, the valve doesn't close - so well pressure causes water to run out of sprinkler heads constantly.
My understanding of the hydraulic valve is: once the pump shuts down, well pressure (thru the small diameter plastic line) is applied to the top of the bonnet diaphragm - since the diaphragm has more surface area on the topside, the pressure applied here is greater than pressure on the underside and the valve closes. If this is accurate, then the pressure on top of the diaphragm isn't greater.

Any ideas?

Wet_Boots

Supreme Member

Posts: 5,165

Location: Metro NYC

22

Tuesday, May 17th 2016, 12:01pm

You are kind of outside the comfort zone on this. What you had may have been functioning only by way of a happy accident. The usual practice for a normally-open hydraulic valve is employ a control pressure that is greater than the pressure you are working with now. What you can do, to obtain positive valve closure, is to employ city water as the control pressure, and to apply it via a Toro 3-way pilot valve.

Another approach to this, is to forget using a hydraulic valve, and go for a power-actuated ball valve.

In the days before affordable actuated ball valves, it would have been more normal to have a set up like a self-contained pump supply. The pump would have a small pressure tank on it and a pressure switch would turn off the pump when a set point was reached. Then it would be the job of a conventional electric zone valve to open and close the flow to the system. That may seem over-complicated, but it's the most straightforward way to cope with the free-flowing well.

By the way, I noticed that tinypic.com may not function if you have an ad blocker. It blanked on my most recent upload until I momentarily disabled Adblock on that page only, completed the anti-bot popup instruction so the upload could finish, then re-enabled it.

corker

Senior Member

Posts: 15

Location: Satellite Beach, FL

23

Tuesday, May 17th 2016, 12:37pm

I was actually thinking of a motorized valve, but at $500 I think I'll check with the shop where I bought the Toro valve first. I could always re-thread the stripped screws in the bonnet of the original valve and reinstall it too. I'll play with this one for a little bit & let you know the outcome.
Thanks

corker

Senior Member

Posts: 15

Location: Satellite Beach, FL

24

Wednesday, May 18th 2016, 2:07pm

Fixed!

OK, I went back to the pump/irrigation store where I bought the valve. Fortunately, the owner was there to help troubleshoot this valve not closing. He said to go back and pull off the 1/4 inch plastic control line that runs from the pump to the hydraulic valve. Also, remove the brass elbow on the pump for the control line and see if they are restricted with deposits. Sure enough the brass elbow was practically closed up and the threaded opening in the pump was just about closed up as well with deposits. I cleaned everything up, flushed the plastic line and the pump and reassembled. I started the pump for a few minutes and then shut it down hoping to see the hydraulic valve close - but it didn't!
I removed the 1/4 inch plastic control line from the hydraulic valve - the orifice at the valve connection is tiny! I ran a pin thru the orifice and reassembled the hose - that did the trick! System works as advertised now. I want to go back to the store and ask if I can open that orifice up a little more - I can see it clogging again. To me, it seems like it will just affect how quickly the valve opens and closes. But, I know it was engineered that way for a reason - I'll run it for a while as-is and see if it fails again.

As I see it, the old valve has a much bigger orifice for the control line and the restricted flow was enough to shut the valve. But the small orifice on the new valve just wouldn't let it work properly. Good stuff and I enjoy troubleshooting a problem to a final solution. Thanks for all your help!

Wet_Boots

Supreme Member

Posts: 5,165

Location: Metro NYC

25

Thursday, May 19th 2016, 8:58am

Just for the record, the new valve you bought was in no way defective in design. They do their job and they do it well. That skinny tubing can control them from a thousand yards away without there ever being a problem. Your particular configuration is something that should have been done differently from the beginning.

This is for two reasons. First, there should never be any unnecessary source of pressure loss on the suction side of a pump, lest it kills the pump performance. Second, these diaphragm valves have a minimum pressure requirement (much higher than your well pressure) for positive closure. Put those together, and you can understand a recommended configuration of pump + pressure switch + pressure tank in conjunction with an electrically operated valve downstream of the pump.

None of this is to criticize your efforts here, but rather to caution future readers with a free-flowing well to save themselves the aggravation that would come from trying to duplicate what turned out to be functional on your system. :thumbup:

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