Should I put it where it is hottest, after the supply leaves the boiler, or on the suction side of the return pump? Can't have both when pumping towards return.
Where to Put Air Eliminator When Pumping Towards Boiler Return?
- Thread starter velvetfoot
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brant2000
Feeling the Heat
I believe it should be on the pump suction side, and ideally at the highest point in the system. Hopefully those places coincide.
Coal Reaper
Minister of Fire
x2 for highest resonable point, zones ussually excluded. i put mine on top of the storage tanks because the flow is really slow at that point allowing any entrapped air to rise. i have also heard if you are on the suction side AND overpumped AND happen to be too close to the circ that there is actually potential to suck air into the system with some of the certain kinds of vents.
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maple1
Minister of Fire
My main eliminator is right before my zone supply header, which is at a high point where the water is likely about its hottest. It is a long way from my circulators though, likely couldn't get any further away - both my zone circ and loading unit circ are at the bottom of my system. I've also got a couple of other small auto-vents at a couple of other high points. None of them are close to a circ. Seems to work out OK. High point is key as that is where the air will go.
I think I'm going to put the Spriovent in the supply manifold after both the pellet and oil boilers, and just before the existing Taco air scoop and expansion tank. I figure, why not leave them there, except for the friction losses, which could be a factor I gues.? I think I'll hook in the expansion tank before the pellet boiler feed pump return and its check valve-that would see the same pressure as the return manifold, I think. A lot of this layout is where to put stuff. It's getting cramped.
heaterman
Minister of Fire
Air eliminator should always be "upstream" of the pump regardless of its location. Correct function will be achieved if the air eliminator is at the lowest pressure point in the system, which is of course at the suction inlet of the pump. Temperature makes little difference.
The other point to bear in mind is that your expansion tank connection should always be in the same place as the air eliminator. Most, if not all, air scoops and separators etc., have a 1/2" tapping at the bottom to facilitate this connection. '
The expansion tank connection is your "PONPC" or point of no pressure change and you want that particular spot to be at the lowest pressure area in the entire system. Putting those 2 parameters together guarantees your sweet spot at which air will be most likely to come out of suspension.
A classic example of low pressure inducing suspended gas/air to "release" for the fluid is the bottle of Coke. If you look at it with the cap sealed tight you see no "air" moving in there. When you break the seal on the cap, you immediately see bubbles forming and rising to the top. Boyle's law of physics states that gas more readily comes out suspension in a fluid at lower pressure. Worked in his lab a century or two ago, works in your hydronic system today. If you fight physics you will always always always lose.
The other point to bear in mind is that your expansion tank connection should always be in the same place as the air eliminator. Most, if not all, air scoops and separators etc., have a 1/2" tapping at the bottom to facilitate this connection. '
The expansion tank connection is your "PONPC" or point of no pressure change and you want that particular spot to be at the lowest pressure area in the entire system. Putting those 2 parameters together guarantees your sweet spot at which air will be most likely to come out of suspension.
A classic example of low pressure inducing suspended gas/air to "release" for the fluid is the bottle of Coke. If you look at it with the cap sealed tight you see no "air" moving in there. When you break the seal on the cap, you immediately see bubbles forming and rising to the top. Boyle's law of physics states that gas more readily comes out suspension in a fluid at lower pressure. Worked in his lab a century or two ago, works in your hydronic system today. If you fight physics you will always always always lose.
My current air scoop is on the supply header, (boiler pumps to return), with an Extrol hanging below it. How well would putting the air eliminator low near the return work on getting rid of big bubbles, not just the little ones traveling along with the flow? There are no bleeder valves on my current system-the air scoop just does it thing-I'm trying to 'improve' thing. You're saying ponpc trumps height and temp?
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