Backflow fitting needed? Is different metals acceptable?

[Cygarbuff]

Hi guys, I had disconnected my black flex irrigation pipe from my back flow preventer since I am on well water now for irrigation. Where I took the gray plastic fitting out I'm looking to put a boiler drain of some sort there. I can't find a drain that has the 1" male threads I need so the guy at Home Depot gave me a 3/4" brass boiler drain with a 1"-3/4" galvanized coupler. Can these two metals come in contact? I've read it will create corrosion issues but I can't find the coupler in brass. If the back flow is copper that brings the total to 3 different metal, can I expect any sort of reaction? Thanks

Jay

 

[hj]

They should have a brass 1 x 3/4 coupling, but you have to look in the brass fitting area. If not any good hardware will have one. Brass and copper are completely compatible.

 

[Sponsor]

 

[Cygarbuff]

They should have a brass 1 x 3/4 coupling, but you have to look in the brass fitting area. If not any good hardware will have one. Brass and copper are completely compatible.

Thank you. I went to Lowes, Home Depot and True Value Hardware with no luck. I'm just going to go to a plumbing supply house Monday. Thanks for helping and confirming

 

[Smooky]

If I was going to use it for irrigation I would not install a boiler drain with a screw on vacuum breaker. I like the poppet style vacuum breaker because the flow is not restricted. Something like a woodford 101 or similar would work.

http://www.woodfordmfg.com/woodford/Wall_Faucet_PDF/101Catalog.pdf

As HJ said above the brass fittings may be in a different area of the store than the boilers drains are located. Sometimes the store associates don’t know the store that well.
http://www.homedepot.com/s/1x3/4+Brass?NCNI-5