Sprinkler backflow preventer - leaking through the top on certain zones

[kissiffer4]

Hi,

I recently started up my sprinkler system and having got past the first hurdle (replacing a valve), the backflow preventer is now causing problems by leaking a ton of water through the top. Strange thing is, it is only on certain sprinkler zones that it is happening. I cycled through each zone and they initially all caused the same behavior of making the backflow preventer leak, however, on a few of the zones, the leaking dissipated after a minute or so and the sprinklers worked correctly as normal. However, on the other zones, it seems like there isn't enough pressure to get the sprinkler heads to pop up and the backflow preventer keeps on spraying a lot of water...and it isn't dissipating at all. Could it be the sprinkler heads are just stuck or might there be broken pipes causing a problem?

Any suggestions much appreciated as you guys already gave me great advice on replacing my faulty valve

Thanks!

 

[Jadziedzic]

The rebuild kits for a Febco 765 (a popular model) run about $25 and are easy to install - you might consider that as a first step.

 

[Sponsor]

 

[kissiffer4]

The rebuild kits for a Febco 765 (a popular model) run about $25 and are easy to install - you might consider that as a first step.

Thanks for the suggestion. I did just replace the existing one with a new one. Also, it does seem to work fine for a few of the zones, 8 and 9, so if it was faulty wouldn't it do the same for all zones? Thanks.

 

[Smooky]

There might be a bit of trash in the valve and it needs to be cleaned out. Did you flush the line before you installed the valve? If that is a constant problem you may want to install an inline strainer/filter to help prevent fouling. ......Maybe there are too many sprinkeler heads or to much flow to build enough pressure.... The spring could be too weak or maybe a torn gasket.

 

[kissiffer4]

Thanks Smooky. Since it works fine on three of the zones i.e no leaking at all and full power to those zones, would the issue you mentioned still be a problem? I'm a novice with this sort of thing so I am probably missing something. Thanks.

 

[Smooky]

If I was there it might be obvious but since I'm not you will have to do some troubleshooting. The more stuff like this you do the more you learn.

Here is instructions for that valve and a trouble shooting section:

http://www.febcoonline.com/pdf/IOM-F-765.pdf

Here is a link that discusses leaks in PVB's that might help you to understand why it could be leaking:

http://homeguides.sfgate.com/sprinkler-pressure-breaker-leaking-102515.html

 

[Gary Swart]

I don' know how your city or state enforces the laws on backflow preventer, but in Washington, our must be inspected and certified annually. The inspector will probably have the parts to repair those that don't make the grade. Enforced laws or not, BFs should be tested each spring. A faulty one would be as risky as no BF at all. Each spring my city send a list of certified inspectors and it is our responsibility to make an appointment with one of them. They come to the home. Normally takes about 15 minutes or less. Cost will vary but my inspector charges $35. The inspector send a copy of the test to the city and f a person tries to slip by without and inspection, he will find his water service cut off.

 

[hj]

The only reason a BFP will leak AFTER it is turned on is if there is not enough water pressure to keep it closed. Apparently your pressure drops when those zones operate so you have to determine WHY the system pressure is dropping.