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Sunday, May 20th 2018, 8:31am

backflow preventer gushing water from the bottom


I have a well to supply my sprinkler and drinking water. This system has a back flow preventor, watts 3/4" 009M3-QT, and is gushing water whenever the sprinkler system is off.

The gushing of water started happening after replacing the 3/4hp well pump with a constant pressure system that maintains 70psi. I tried using pressure reducing valve but it didn't work.

Is there another type of backflow preventer I should be using? or is there something that need to be added to my sprinkler sprinkler system to reduce the higher pressure?

Thank you


Active Member

Posts: 42

Location: Washinton


Friday, May 25th 2018, 11:49pm

Most likely what happened is some trash got into the line and contaminated the backflow, in which case it starts to dump water.

You can open up the backflow and see if anything is obstructing the plunger. When you put it back together try closing the discharge side of the backflow then open the inlit side of the backflow as soon as possible this will allow the water to seal the plunger as quickly as possible.




Thursday, July 26th 2018, 7:08pm

Is this backflow really brand new?

One contractor sold us this stuff for $505 and claimed it’s brand new, I feel a little bit skeptical.... why it’s powdered white in the middle, not like what I saw on amazon all brass? any idea? Thanks.



Supreme Member

Posts: 5,331

Location: Metro NYC


Friday, July 27th 2018, 7:25am
You are probably looking at Zinc Oxide. The temperatures for casting brass are fairly close to the melting point of zinc, so a bit of zinc might migrate to the surface of the cast part, where it can later oxidize. Do not worry about it.

And do not paint the backflow preventer.

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