# Location of air separators?



## EricO (Sep 1, 2014)

SO I know that I need an air separator in my system, but my question is where and how many.  I will be using Slant Fin Multi/Pak baseboards, 2 - 3 zones depending on final planning.  Reading the installation manual, if I understood it correctly, it says to install an air separator at each riser.  If I'm not mistaken, that would be each time the supply line comes up from under the floor, I need a separator?  So where exactly should i put them?  I made a goofy little sketch to help illustrate my question.  

Do i put the separator at point A or point B?  Or somewhere entirely different.  Any guidance on this topic would be MUCH appreciated.  

-Eric

PS- I will be installing a pensotti radiator in one of the rooms.  Does it need a separator as well?


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## Bob Rohr (Sep 1, 2014)

EricO said:


> SO I know that I need an air separator in my system, but my question is where and how many.  I will be using Slant Fin Multi/Pak baseboards, 2 - 3 zones depending on final planning.  Reading the installation manual, if I understood it correctly, it says to install an air separator at each riser.  If I'm not mistaken, that would be each time the supply line comes up from under the floor, I need a separator?  So where exactly should i put them?  I made a goofy little sketch to help illustrate my question.
> 
> Do i put the separator at point A or point B?  Or somewhere entirely different.  Any guidance on this topic would be MUCH appreciated.
> 
> ...




You need a central air separator near the boiler, the hottest point in the system which is the supply from the boiler.  Use a micro-bubble type not a cast iron, ramp style air purger.

Additionally, install an air vent at high points in he system, like that radiator.  It can be a coin vent style, or hygroscopic.  No need to have a vent at every baseboard ell.

If you plan and pipe the system correctly, the air separator at the boiler does all of the work.  High point air vents capture air that rises up during down times.

A few tips:

Pumping away from the expansion tank proper expansion tank and pre-charge.  By far the biggest error in hydronics is pump to expansion tank relationship.
Static fill pressure in the system to assure 5 psi at the highest point in the piping.
Pipe sized to assure 2-4 fps feet per second fluid velocity.
A valve and purge cock located to power flush all the zones for start up.  Webstone makes nice valves for this application.

Most air problems and related issues such as noise, erosion and poor heat exchange are due to installer error.

Hot off the press a technical journal with current air and dirt removal concepts.

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_15.pdf


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## ewdudley (Sep 1, 2014)

Your runs should rise continuously to downstream high points.  Every high point that could collect air needs a 'coin vent'.

Micro bubble separators are  mostly useful for covering up problems, although they can also be convenient for saving one round of bleeding during system start up.  You can use a traditional cast-iron ramp type air separator and save a lot of money if you're willing to re-bleed the baseboards after things have settled down.

Once the system is stable you can seal off any 'auto' vents since they all will leak eventually if left open.  There should be no more air anywhere again unless the system is 'opened' for some reason.


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## DaveBP (Sep 2, 2014)

Is this a closed, pressurized system? Open system running off an outdoor wood boiler? 

This stuff makes a difference.


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## heaterman (Sep 2, 2014)

*Is this a closed, pressurized system? Open system running off an outdoor wood boiler?* 
That question must be answered before anything else can be applied.


If your system is closed/pressurized, Hot Rod (Bob Rohr) has it pretty much nailed.
I'll reiterate that you do not need or want an actual air sep at all your system high points.
A simple coin vent/baseboard tee will suffice at the end of each baseboard zone before it heads back to the basement.
(in your drawing it would be on the last baseboard, right hand end)
Pumping away from the expansion tank/air scoop location is the most important thing you can do.
Installing a purge tee arrangement is the second most important.


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## EricO (Sep 3, 2014)

Thanks for all the help you guys.  The funny thing about asking questions on a forum is that you have all the workings of your system in your head, and other people don't know what it is.  Even if you include information, there's still much more to be asked! haha.

The system is going to be a closed system.  Bob Rohr, a big thanks to you for that manual.  It was very helpful and actually answered questions on several other fronts as well.  I'm planning on having one air/dirt separator, and then an automatic air vent at the end of each baseboard section before it goes back down into the basement.  The air vents are HAV auto air vent with manual override - I believe it's one of the ones that expands or contracts depending on if it's wet or dry.


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## heaterman (Sep 3, 2014)

Where are you at in "the Tip of the Mitt" Eric? I was up to Gaylord last week looking at a job.


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## BoiledOver (Sep 4, 2014)

Bob Rohr said:


> Hot off the press a technical journal with current air and dirt removal concepts.
> 
> http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_15.pdf



Hey, that is some good stuff. Thanks for posting the link. Cripes that outfit has an entire encyclopedia set on hydronics or (idronics)..


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