excess air in circulating water

[kengolive]

Hello 
I have a common problem in my conditioner and it is (we call it) “excess air in circulating water”. We have a Fan Coil Unit and you should know that the air bubbles in a closed system like any coil system could lead to performance problems. You cannot have the maximum performance if your cool/hot water in the coils has more air within it. So we have to release excess air by opening and closing a valve (bolt/screw) and air is trying to escape because there is always water pressure in a closed system.
(Every FCU has its own screw for escaping air)
Now the question is what is the best situation for releasing excess air? I mean, when the water is circulating or just when the system is shutdown?
1. Release excess air when water (hot/cold) is circulating
2. Release when the pumps are off
I don’t know the difference and the better way for doing this, please help me. By the way, I couldn’t find the technical definition/phrase for this “excess air in circulating water”; would you please tell me what you call it?
Regards,

[Repair-man]

So this is a "swamp cooler"?  More on those here:
http://www.mobilehomerepair.com/hvac/ArticleSwamp.html

http://www.opalcat.com/Information/swamp-coolers

[Icehouse]

Why not use "Automatic Bleeders" like the ones on Hydronic Systems

[kengolive]

I really don’t know why “Repair-man” did refer me to a swamp machine?! Would you please someone tell me?
Anyway, that’s it “Icehouse”; we have a “Two Pipe System” of Hydronics, one for hot water and one for the return path to boiler but there is no automatic bleeder. We should release our air bubbles through a manual valve.

[kengolive]

 “Icehouse” leads me to the right place and I found out that the problem in our “Water loop system” is just called “Entrained air” and Entrained air is the air bubbles that travel around in the piping at the same velocity as the water. Air "scoops" are tools/products which attempt to remove this type of air and we use these Air Scoops.
So, now the question cleared: when should I use air scoop to release air?
1. System running (water circulating)
2. System shutdown (water not circulating)
Have a nice circulation system :-)

[Repair-man]

We call them swamp coolers here if they use water to cool the air. It's a colloquial term. 

Why would Ahmadinejad come to New York and state that there are no homos in Iran?

I'm still laughing at that one

[kengolive]

Dear “Repair-man”,
If you pay enough attention in what did I said, you will probably know the exact things I mentioned. I said “Fan Coil Unit” and “coils” and “hot water” and so many words that are simply enough for “I have not a swamp cooler”, did you read the entire post?
Anyway, I hate Ahmadinejad by myself but don’t you think that is a technical forum? By the way, you can listen to more funny things from jw bush or any other politician in the world  there are a couple of homos here in IRAN of course, want to come here?