I was using a 1/8" solenoid… if you do the math 1/8" x 2 = 1/4" right?
So size should be ok.
Depends on orifice sizes. But generally speaking area of 1/4" is 4 times the area of 1/8".
ok so the horn im using is off a firetruck and uses 1/8th in line. but i was originally using 1/4 in and went up to 3/8th. it worked with the 1/4in at 150 psi off regulator but the horn should only need 90psi to work. i thought maybe if i got more air flow it would help so i went to 3/8 in. With the 3/8in it worked the same as the 1/4 and all of a sudden one day i stopped working. i checked all the tubing and there is no hole and the solenoid still works.
I’m not a genious but i’ve always thought that 1/8 is the perfect half of 1/4…
By the way in my experience never use bigger tubing along the way.
What i mean is… if i run 1/4" tubing before solenoid i cannot use 3/8" after the solenoid…
I know it is not your case but… keep this in mind this for the future.
Tank is ok, tubing is ok (you can blow your horn without solenoid), solenoid is ok (you claim that)… if horns are ok too i don’t know what the problem is.
Once again i’d rebuild the system from the beginning.
Just curious, could you tell me the size of both tubing from solenoid to horns?
i originally used 1/4 in before and after solenoid then i was told i needed more air flow and bigger tubing so i then went to 3/8in tubing. my issue im having is that im not getting the pressure out of the solenoid that im putting in
Common misconception. It’s the cross-sectional area that counts…not the diameter. Area=pi*r^2
1/8" diameter-----> 3.14 * .063 * .063 = .013 sq inches
1/4" diameter-----> 3.14 * .125 * .125 = .049 sq inches (almost 4x)
Bigger airlines/fittings/components can’t hurt airflow or pressure no matter where they are in the system.
One last idea…Is the valve installed the correct direction??? There should be an arrow on the valve body. Or “IN” and “OUT” on the ports.
Otherwise I’m with tuononero - pretty much out of ideas.
:o ehm ok 
I think that it would require more time to operate tho. I would never use bigger tubing on a restriction. I mean, if i had a 1/4" solenoid i’d use 1/4" tubing, not
1/2" tubing on a 1/8" horn… it doesn’t make sense to me.
BTW the arrow on the solenoid is another thing to check… even if as far as i remember the other horn works… so it’s not the problem.
is there a difference between these solenoids?
http://www.hornblasters.com/products/details.php?i=1-4-in-air-valve
http://www.hornblasters.com/products/details.php?i=smc-1-4-in-air-valve
Just the manufacturer
Metal vs. Plastic
The brass one flows twice as much.
The brass one handles 217psi vs. 150 for the plastic one.