Help With an Automatic Sprinkler System Issue?

[rp2813]

One of the lines in my sprinkler system is misbehaving.  When operated via the timer, the line receives only a partial flow of water.  When I go to the valve and operate them manually, they work fine.  I've eliminated the timer and related wiring as the possible cause.  I changed out the solenoid on the valve itself, and only saw slight improvement.  Before installing the new solenoid, I opened the valve to clear out any possible clog from debris in case there's a difference in routing of the water based on whether the valve is operated manually or via the timer, and I got what appeared to be a decent flow.

 

Is it time to replace the valve itself?  I don't know what else could be causing the problem, but we are quickly heading into irrigation season here so I need to get this fixed.

 

Any suggestions for further analysis would be most welcome.

 

[revvinkevin]

Hi Ralph,

While I am far from being an irrigation expert, I suspect it's the valve itself. I'm having a few issues with my system and one circuit is doing pretty much the same thing. A friend suggested replacing the valve, but with the pending wash-in looming in the very quickly approaching future, it's not exactly on my priority list at this moment.

Kevin

 

[yogitunes]

not sure about your system....but on mine, theres the solenoid on top, which can be turned to operate manually, and a sleeve type collar under this that can be turned to adjust water flow and pressure, you have to hold the top solenoid section in place while you turn the collar.....this might help you.....

also this whole unit can be unscrewed and taken out, to which there is a screen that needs to be cleaned once in a while....

 

[twintubdexter]

I am no expert for sure, but I was the plumbing buyer for OSH for many years and irrigation was a huge part of that...replace the valve, they are not worth trying to repair unless you have some exotic professional system...good luck.

 

[rp2813]

Thanks to all for the input thus far.  I think Kevin and Joe's responses are indicative of the ultimate repair that will be required.  It's time to go valve hunting and figure out what fittings I'll need since it will require hacking through the PVC in order to remove the valve.

 

Martin, the valves all use a similar system to yours but I don't think there is any collar like the one you described where the solenoids attach, and no screen that I can see.  Also, my valves have a large plastic screw at top rear that can be turned by hand, which allows for manual operation without disturbing the solenoid.

 

[twintubdexter]

Your valves are most likely installed with 3/4" schedule 40 pvc. If the valve is close to the ground it's a good idea to extend the pipe 6 or 8 inches with a slip coupling and a short piece of pipe (nipple) then glue the new valve on since the day may come when the valve needs replacing a second time. You will have enough of the pipe extending when you cut the valve off again and glue on a new one. Of course the manifold your valves are installed on may be different. Go to OSH and ask a salesperson or the department manager for help. If they don't give you the advice you need, slap them silly and tell them it's from the old buyer.

 

[variflexpghpa]

What brand of valves?

I have Toro valves on my sprinkler system and they are easily repaired. I am sure the valve body on your valve in question is fine. On the Toro valves you can replace the diaphram and/or the solenoid quickly. Also on Toro valves, there is a bleeder hole on the diaphram which can get clogged which sometimes causes the valve to hesitate on opening or closing, and I am guessing could keep the valve from opening fully. In your case, I would try to get a valve rebuild kit and not have to go to the effort to remove the valve body.

 

[dogboy44]

Solenoid

Replace the solenoid. I have had the same thing many times. Easy and cheap.

 

[rp2813]

1) I don't see any way to take the valve apart. I would definitely have done that if it were possible. I think mine are throw-away items.

2) I already replaced the solenoid and there was no change.

Joe, your suggestion validates the plan I had for this repair, and for the exact reason you stated. I'm fairly certain it's 3/4" PVC, and I might be lucky enough to have a scrap length of schedule 40 around here somewhere. The actual valve and fittings may be all I will need to buy.

 

[sudsmaster]

Is it possible the timer is opening two valves at once, with the other one just leaking water somewhere unseen?

 

[rp2813]

Rich, that's highly unlikely.

The pressure here is so bad, and combined with 85-year old pipes, I can't imagine operating two lines at once would result in more than dribbling from both. Currently the line with the problem is operating at approximately 2/3 flow at most.

 

[twintubdexter]

now watch someone say I'm crazy...

All it takes is a piece or two of gravel in the valve to cause the plunger and/or diaphram to malfunction...the valve sticks, leaks, won't open, won't close or there's less output. You probably have Lawn Genie valves. Manufactures offer repair kits because, especially from a retailer's standpoint, customers would be upset if they were told "sorry, you have to replace the valve." I'll bet we got thousands of returns on solenoids because anytime a valve malfunctioned customers would try that since it was cheap and easy to install. The valve repair kits with their many parts were "less friendly." A 3/4" slip/slip Lawn Genie anti-siphon valve costs less than $20...cut the old one off and stick a new one on. Check to see in the old valve and new valve have the same footprint.