Lawn Sprinkler Question

[kyleb]

I got home from work today and water was running across our driveway. As it turned out, one of the sprinkler valves in the valve box was "on" and water was running through it. I manually turned the valve to "off" and checked our sprinkler controller. The controller was set in the "off" position and the timer was not set to activate any of the zones, any time of day, any day of the week.

So, why was one zone running today given that we haven't used the sprinklers in months?

Can valves fail "open" or is there some other explanation?

BTW, I unplugged the sprinkler controller from the wall after I turned the individual valve off.

 

[asicer]

Can valves fail "open" ...?

Yes

 

[SoonerAviator]

You should also be able to shut off the "main" into the sprinker system, assuming it was plumbed properly. If a valve fails open while you aren't actively using it, it won't matter because there's no pressure in the system with the main shut off.

 

[Cap'n Jack]

I once had one stuck open- a piece of junk kept the valve from closing. I've no idea how it got into the water system. As your system has apparently been unused, I doubt this is the issue.

Check that the controller isn't sending power to the valve (valve needs 28 V. It is likely AC, not DC). A ruptured diaphragm in the valve could cause it to open too.

 

[kyleb]

You should also be able to shut off the "main" into the sprinker system, assuming it was plumbed properly. If a valve fails open while you aren't actively using it, it won't matter because there's no pressure in the system with the main shut off.

I'm gonna have to look for the main cut-off for the sprinklers. I've never seen it. It isn't in the main water valve box. The tough thing is it is dark outside this time of year when I go to work and also when I get home, so finding the box may be a challenge. Oh, and the fact that I haven't noticed a separate box in the 14 years we've been in the house.

 

[SoonerAviator]

I'm gonna have to look for the main cut-off for the sprinklers. I've never seen it. It isn't in the main water valve box. The tough thing is it is dark outside this time of year when I go to work and also when I get home, so finding the box may be a challenge. Oh, and the fact that I haven't noticed a separate box in the 14 years we've been in the house.

If you're lucky they did it properly with a main cut-off. You never know what you're going to get with a landscape crew. We normally plumbed them at the side of the house where the water main comes in with a backflow preventer. Like this:

 

[Lindberg]

Likely needs either a new diaphragm or solenoid. HD carries the parts for the major brands.

 

[kyleb]

If you're lucky they did it properly with a main cut-off. You never know what you're going to get with a landscape crew. We normally plumbed them at the side of the house where the water main comes in with a backflow preventer.

I can put hands on the backflow preventer and the main where it comes inside. There's no sprinkler "T" there. I have a very faint memory that there is a second water "box" somewhere between the outside shut-off and where the water comes into the house. Maybe I'll try to work from home on Thursday and find that sucker. Supposed to be 25F warmer here on Thursday anyway.

 

[kyleb]

Likely needs either a new diaphragm or solenoid. HD carries the parts for the major brands.

A couple of questions:

The system has been "off" for some time. Presumably, no power has reached the valves since then. (Is that a good or bad assumption?)

When I turned off the valve that was flowing water, it was a matter of turning the valve handle until the flow stopped. Would that stop the flow if the diaphragm was bad?

 

[flyingron]

The valves frequently get stuck on because they accumulate crud in them.

This lawn supervisor was out on a sprinkler maintenance job and he started working on a Findlay sprinkler head with a Langstrom 7″ gangly wrench. Just then, this little apprentice leaned over and said, “You can’t work on a Findlay sprinkler head with a Langstrom 7″ wrench.” Well this infuriated the supervisor, so he went and got Volume 14 of the Kinsley manual, and he reads to him and says, “The Langstrom 7″ wrench can be used with the Findlay sprocket.” Just then, the little apprentice leaned over and said, “It says sprocket not socket!

 

[Lindberg]

A couple of questions:

The system has been "off" for some time. Presumably, no power has reached the valves since then. (Is that a good or bad assumption?)

When I turned off the valve that was flowing water, it was a matter of turning the valve handle until the flow stopped. Would that stop the flow if the diaphragm was bad?

Can you see the brand of valve?

 

[kyleb]

Can you see the brand of valve?

I'll give it a shot later in the week.

 

[flyingron]

If it's a Hunter valve and you've verified that the water is shutoff feeding the valve, remove the four (or six) screws at the top of the valve cover and lift it off. Inside is a spring and then a white plastic diaphragm. Under that a ring with a lot of holes on it. Flush all out in clean water to make sure that any sand or other debris is cleared off and then reassemble the thing. It should shut off now. If this happens repeatedly on different zones, you probably need a little sediment filter on the feed to the thing.

 

[Cap'n Jack]

A couple of questions:

The system has been "off" for some time. Presumably, no power has reached the valves since then. (Is that a good or bad assumption?)

When I turned off the valve that was flowing water, it was a matter of turning the valve handle until the flow stopped. Would that stop the flow if the diaphragm was bad?

Also check the voltage to the relay. It should be 0 volts when off.. A failure in the controller could energize the relay.