Anti-Siphon valve 30 in. ----what does 30 in mean

Prophammer

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I just bought a new anti-siphon valve for my boat. The one I got is an Attwood 30 in. - it is 1/4 NPT with a 3/8 barb for the hose, what does 30 in mean ?
 

Prophammer

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Attwood part number on the packaging is 88FAS014-6 (30 is stamped on the part itself) what does the 30 mean?
 

GA_Boater

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It means Attwood stamped "30" on the valve. Why does it have to mean anything to the consumer as long as it works?

It could mean "Passed by Quality Control Inspector 30" and the the part is too small for all of that, so only "30" was used. :watermelon:
 

alldodge

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Attwood part number on the packaging is 88FAS014-6 (30 is stamped on the part itself) what does the 30 mean?

Took me a bit and you learned me something, so its a good day

Anti-siphon valves are required by Federal Law and the USCG on all permanent fuel tank installation. Use 15 (Brass) calibrated for HP 200 & above and 30 (Aluminum) calibrated for HP below 200.

The 30 is Type 30 aluminum and must be used for motors under 200 HP
Aluminium He30 as a medium strength alloy with excellent corrosion resistance.

Brass must be used for motors over 200 HP
 

racerone

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Does the 30 in.have to do with the strength of the spring ?-------Perhaps related to how high the valve can be before siphon action pull it open ?
 

GA_Boater

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Then the inspector stamps the 30 or 15 so it does mean something to the consumer.

You learned me something, AD.
 

Prophammer

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I don't think it means 30 inches of vacuum , 30 inches of vacuum is un-achievable on earth, I was thinking it might mean the length of of the pick-up tube , but I don't want to assume anything, thanks for all replies
 

Prophammer

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I hope it's not against the rules, I checked another forum and got this answer:

"" 30" of water is the pressure or vacuum needed to unseat the ball check valve.
The older Evinrude service manuals ilustrated an anti-siphon valve test consisting of 3' of clear tubing held vertically with the valve at the lower end. You added water slowly until the valve passed water through it. The column of water in the tubing should hold at around 28" of water and leak at around 29" if I remember right.""


It makes sense to me now , thank you all
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Prophammer

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hmm, type 30 aluminum , I learn something new everyday, I'm going to research that , yes
 

dingbat

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Google fact checkers...lol

HE 30 is a long obsolete (1980’s) British standard designation for a 6082 aluminum alloy. Thus the reference from a website in Mumbai, India.

Here is the list of International alloy designations and chemical compositions of aluminum alloys.

Aluminum alloys....Four (4) digits with three (3) digit temper designations....ie 5052-H32

https://www.aluminum.org/sites/default/files/Teal Sheets.pdf
 

Prophammer

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I think I found the correct answer ,,, now I feel really bad because it came from another forum ,,,,,The correct answer is:

For the 30" label/spec of an ASV, that is the maximum height of the fuel level in the tank to the lowest part of the fuel system and is usually referenced as the "head". In other words, the valve will seal against a leak up to 30 inches below the top of the fuel level.


Thanks to all; because any input is food for thought and greatly appreciated
 
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