I’ve got a sprinkler system that came along with the purchase of my home. It appears someone had replaced one of the ball valves from original and before I owned it probably wasn’t winterized correctly and is thus cracked. I know I need to replace the ball valve and not try to repair but was wondering if I should just replace the ball valve or the whole vacuum breaker? And is there a way to determine from markings what size it is? Wasn’t sure if 765-1 meant one inch?

It does mean 1", that's kind of big...is the feed and discharge on it 1 inch.... most are 3/4"

This isn’t my strong suit but I believe so. Both ends are screwed right in to the ball valves on either side of the 765-1. One is the hall valve that came with it. The other(the cracked one) is a matco norca 600 WOG-150SWP. Both are threaded and don’t appear to have any sort of adapters between them and the main pipes.

You have a pressure vacuum breaker backflow preventer. There are lots of water protection laws that surround backflow preventers and their use. I just got licensed to install, test and repair backflow preventers.

Febco is owned by Watts. Go to this webpage for installation and repair instructions:
[www.watts.com]

Your backflow preventer has some numbers on it. Take a picture or write them down. The markings may be near the serial number. You need the manufacturer, model number and the size. All of this should be obvious on the backflow preventer.

Go to your local plumbing supply house and order the exact ball valve (same manufacturer, model number and size) that you are replacing.

Install it. It is okay to replace just the broken ball valve.

Technically, at this point you are supposed to have it tested by a backflow prevention tester.

Be sure and keep your receipts to show that you installed the correct manufacturer's replacement part.

Usually backflow preventers must be inspected once per year and a report turned into the city. Some cities are lax on making sure they are inspected. Normally, you pay a plumber or a backflow prevention tester to check them.

You are supposed to replace broken parts with manufacturer supplied parts. I have spoken at length about part replacement with the University of Southern California (USC); the USC is the top accreditating agency for backflow preventers. I was trying to find wiggle room around using manufacturer supplied parts. I had no such luck.

The purpose of your backflow preventer is to protect the general public, via the water supply, from the chemicals which you put on your own lawn (insecticides and fertilizer).

When a backflow preventer fails the water near the sprinkler heads can get sucked (back siphonage) or pushed (back pressure) into the city water system. And then you have a mess.

Backflow preventers usually fail because of worn out valve seals or contamination by dirt or debris.



Edited 5 times.

if the ball valve cracked (It froze!!) it's time to replace the whole backflow and start draining it every fall. Why spend the time and money just replacing the ball valve...put it all back together only to fine it leaks somewhere else on the unit.

Ok. Life happened. Finally getting back to this project. I went to look at it again. It was put on with Teflon tape. Can I just unscrew or or do I actually have to cut the pipe off or something?