Air Scoop or Air Eliminator?

Cyclist77

Is one preferable over the other? Currently have a Taco Air scoop but will be replacing my boiler and as the components are 15 years old I am considering replacement.

Thanks

Derheatmeister

I Personally perfer the Mircro Bubble type such as the spiro Vent especially when the Mechanical room is small/constraint…Taco Air scoops require at least 12" of straigth piping prior to it to work correctly

Webstone makes a good air eliminator for the price.

HR will probaby explain why The Big C is Better. 😊

mattmia2

I think you're a lot more likely to get repair parts for Caleffi 20 years from now.

The microbubble separator if located between the outlet of the boiler and suction of the circulator does a great job of removing the last traces of air that you can't purge or bleed out.

Mad Dog_2

Spirovent or Caleffi. Mad Dog

leonz

https://forum.heatinghelp.com/discussion/200288/air-scoop-or-air-eliminator

Air scoops do not go bad, you can make your life a lot easier and not have any maintenance to do ever if you eliminate the bladder tank and connect the air scoop top tapping to an AIRTROL valve connected to a steel compression tank. A little more work but no bleeding of baseboard-ever.

You can eliminate the air scoop and install an Internal Air Separator and connect it to the AIRTROL valve and strip the air bubbles out of the water as it is pumping away.

The smallest B+G steel compression tank is 15 gallons and when it is installed with the airtrol valve it has a 5 gallon air volume and 10 gallons of water to create the point of no pressure change. The air bubbles that enter the air scoop or internal air separator rise up and enter the airtrol valve and are absorbed by the air blanket and the cool water in the steel compression tank falls down the cold water passage back to the system replacing the air bubbles that rise up into the airtrol valve.

hot_rod

as the name implies air seps gets the microbubbles out, usually within a few passes

The Discal has a large chamber for a low velocity zone, and a large non metallic media

It can be disassembled at top, usually by hand, to clean or replace the float and needle valve

Micro bubbles form when heat is applied to metal, go put a pan on your stove, a cup of water in it, turn on the burner. What do you see happening at the bottom of the pan after a few seconds?

In a closed loop system those bubbles need to be moved out, or they go back into solution when the water cools, snd the cycle repeats.
Ramp type purgers struggle to get those tiny bubbles

So heat transfer in the boiler and in the heat emitter suffer with bubbles instead if water in contact we the metal

A camel hump purger is really not much more than a coupling

Do a search and see how many air issues come across this site.

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EdTheHeaterMan

True story: There was a Post Office in Dennis Twp., NJ that was connected to the home that the post master lived in. The CH boiler was located in the basement and there were at least 5 different zones operated by zone valves and one circulator pump located on the boiler return. The expansion device was the older 30 gallon compression tank strapped between the ceiling joists in the basement above the boiler.

For the 14 years that I did the annual maintenance on that home, (and for years before they were my customer) the expansion tank would need to be drained at least 2 times per year. The Post Master/Homeowner would need to let air out of the radiators on a regular basis, and I would need to come and purge the baseboard loop zones at least once a year. It was just the way this system worked and the guys that worked for me knew that this was just the way it was.

At one point the boiler started leaking (Go figure with always adding fresh water over the years). and U had just finished a Dan Holahan Class on Hydronics. My company was awarded the contract to replace the boiler and I gave specific instructions on where the new Extrol 30 tank was to be installed on the supply pipe out of the boiler. I spent a crazy high price for one of those new Spirovent things that has just come on the scene. And I wanted the circulator to pump away from the expansion tank. My seasoned boiler installer thought I was crazy.

When the boiler was finished, and filled with water, it was about 4:30 in the afternoon on the second day of the job and my installer started to pack up to return tomorrow to do the purging and venting of air that was sure to be another 1/2 day based on our experience with this job. I said Hold On. Purge the loops while I do the cast iron zone with my radiator key, these folks are getting heat tonight. Within 30 minutes the boiler was ready to fire up and my boiler installer was amazed that the water circulated on each zone and the Spirovent was dumping excess air from the zones until each loop returned Hot back at the return. This Known "Air Problem" system is now a system that automatically removes air from the radiators while operating. You just need the let the science work for you … NOT against you!

hot_rod

I’d guess from watching the job pic here, over the years maybe 1 in 10 air scoops are installed per the manufacturers instructions.
I’ve seen different straight pipe requirements, most show 18-24” some use to show that dimension based on the pipe size. Some brands have scrubbed the required distance from the installation completely.

Assuming you have 18” and velocity is below 4 fps which I doubt anyone confirms😳You still have no mechanism to grab the micro bubbles, some of which are smaller than the eye can see.

Time was when the auto vent screwed into the top of the cast iron boilers did most if not all the air removal work. As such the purger became more of an expansion tank bracket.

The small, thin metal, high wall temperature, high velocity coil type mod con heat exchangers really need and deserve a microbubbles device . But even fire tube and cast boilers get a boost in air removal efficiency and speed with air separators.

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leonz

Bob, I do not know how to do this, but do you have a drawing of the Internal Air Separator (IAS) connected to the airtrol valve and steel compression tank and a drawing of the air scoop connected to the airtrol valve under the steel compression tank that you could also post for the forum?

Thanks much,

Leon

hot_rod

https://forum.heatinghelp.com/discussion/comment/1839230#Comment_1839230

The B&G diagrams?

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leonz

Yes Bob,

thank you, they show how simple and effective the IAS, AIRTROL and steel compression tank are able eliminate air bubbles and maintain point of no pressure change AND also keep the weight of 10 gallons of water pressurising the system at all times eliminating any requirement for a bladder tank to create a point of no pressure change.

The Internal Air Separator has a cast in place baffle that diverts any air bubbles upward through the top tapping and the air bubbles and micro bubbles rise into the Airtrol valve and dissolve as they rise in the water in the Steel Compression Tank. The cool water in the steel compression tank falls into the cold water side of the casting and sinks back into water stream being pumped from the boiler to the heating load.

My system operates at a very low pressure with a single loop of 225 feet of fin tube baseboard.

The other thing is the water fill valve does not have to be left open EVEN WHEN using a bladder tank after a system is bled.

hot_rod

The IAS does seem to be more engineered than the basic ramp style. But my money is still on any of the microbubble resorbers for 97% efficiency.

Cyclist77

Bob, those pics are very helpful! Thanks!

mattmia2

the height of the water creates pressure, not the volume. and only if the top of it is open to the atmosphere.

leonz

The 83 pounds of water in the 15 gallon compression tank are bearing down on the 3/4" tapping entering the fluid flow.

hot_rod

Caleffi can fix most any air problems

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mattmia2

you could direct that to a compression tank to replace the fittings that b&g no longer makes