vacuum breaker replacement

0100010

Not Sure

Joined: Jan 2003

Posts: 18906

EE: 100% (5)

TX, USA

Posted: 9/3/2026 5:00:57 PM EDT

Short answer : users should check if SpigotMaster has a adapter first.

Long answer :

The hose spigot / bib / silcock in my backyard, the anti-siphon valve present started leaking when using the hose.

OK, BTDT, had to replace them on the last house too. Swing by Home Depot, picked up the usual anti-siphon valve they have (Arrowhead PK-1390?) and head home. Unscrew the current valve, attempt to attach the new valve - nope, wrong threads, won't fit.

OK, take pics of the current spigot to ID the manufacturer; Matco. Find Matco-Norca, search replacement anti-siphon valve, find part 646ASCLF, order that. It arrives, and again - wrong threads, won't fit.

Reach out to Matco-Norca. They put me in touch with the regional guy who says, the correct replacement valve is part number AZ646ASLF. Go look for that and it is not listed anywhere. So reach out to the plumbing supply houses in my area, Coburns, Reece, Texas National. Request quotes for this part. They never respond, likely cause I am just a homeowner, not a contractor.

Get pissed off. Order the entire replacement spigot, with a new anti-siphon valve from Coburns.

Think to myself, there has got to be someone who makes a plain threaded adapter with no anti-siphon function to solve this problem. Find SpigotMaster, who sells just that on his site and through Amazon. Measure the threads on my spigot, order what I think is the correct part via Amazon. Then the SpigotMaster guy calls me, to get pics / measurements, to be sure he is sending something that will work. Ordered the 'SM05' model, he sends the '1.125' model. Install it upon arrival and it fits perfectly.