Heating Boiler Air Scoop FAQs

Q&A on Bulk Air Separators & Air Purgers
Installation, Troubleshooting, Repair

Air Scoop Location FAQs

Where does the air scoop belong: boiler outlet or boiler return?

I understand that I want an airscoop before the pump (point of lowest pressure) yet a British lad on YouTube said you want to put the airscoop behind the pump cause otherwise the pump will be sucking air in?

So how far from the pump should I go back? On 2019-03-12 by Andreas

by (mod) - best practice, air scoop at boiler supply out & the circulator pump is on the return side of the boiler

Andreas

Bottom line: Normally and as is best practice, the circulator pump is on the return side of the boiler

and the air scoop is above the boiler on the outlet or supply side side. That avoids the problem that you were discussing.

Details: Frankly, the claim from that British Youtube Lad is nonsense.

If there is an air vent atop the air scoop, it's a float type vent that uses a one-way spring-loaded Schrader valve that lets air (or water) out but not air or water in.

Furthermore, the boiler water at that point is always under positive pressure, at somewhere between 12psi and just under 30 psi. Air at atmospheric pressure isn't going to leak into the system unless the system is being drained or emptied and the valve is held open (which is tricky to do).

If the circulator is on the supply side of the boiler, it's pushing water up out of the boiler past the air scoop, not "sucking water" down from those pipes.

If the circulator is on the return side of the boielr where it belongs, the boiler is pulling water out of the heating zone pipes and pushing it back into the boiler - nowhere near the airscoop.

I want to lower my Taco air scoop to allow additional zone piping

I need to add additional zone to my hot water system. To accommodate the room for an expanded header manifold can shorten my 2"black iron feedpipe by 18", which will lower my Taco scoop making closer to the boiler then turn the 2" Black Iron back up giving me more room to expand the header.

I didn't know if the scoop needed to be at the same height as feed manifold. -On 2018-01-27 by Jim U

by (mod) - proper location for the air scoop at a hydonic heating boiler

The air scoop needs to be at a local high point over the boiler. There are recommended distances and locations that depend on the model and type of air separater "air scoop" that you have installed.

See the examples and installation sketches in this TACO AIR SEPARATOR INSTALLATION GUIDE [PDF]

 

Do I need to move my expansion tank to below the air scoop?

Most scoops call for attaching a diaphragm expansion tank (actually just provide a little picture) to the bottom portion of the scoop. I already have an expansion tank that comes out the back of the boiler. Can I keep my tank at that location or do I need to move it to the air scoop location?

Thank you in advance. On 2017-08-30 by Chris H.

by (mod) - no; does air scoop have a working air vent ?

Chris,

As long as the air scoop has a working air vent you should be OK.

That air scoop mounting point is a convenience, not a requirement.

Air Scoop Replacement FAQs

Can I use a larger air scoop to replace my smaller damaged old one?

Can I use 1 and a quarter-inch diameter air scoop when the old cracked one was a 1 in. would it make a difference to just neck down the bigger scoop to the 1in coper pipe

Can I use a 1 1/4" air scoop when the old cracked one was a 1 in On 2018-06-09 by Anonymous

Reply by (mod) - Air Scoop Size should match heating pipe size

Anon,

Thank you for the interesting question about whether or not an air scoop size needs to be matched to the line size on which it is installed.

According to the Taco air scoop and air Eliminator installation manual that you can find link to in AIR SCOOPS SEPARATORS PURGERS, each air scoop size is designed for the line size to which it is intended to be attached.

That's another way of saying the air scoop size should match the line. That's because air scoops and eliminators are designed for a specific water velocity and volume through the device.

So for best results match the air scoop size to the line size of your heating system.

See details in this TACO AIR SEPARATOR INSTALLATION GUIDE / MANUAL [PDF]

Tell me when to replace the air separator

My 30yr old boiler is being replaced do i need to replace taco air scoop? (Aug 21, 2011) john

Reply:

John I don't see any reason to replace the air scoop unless it's corroded or clogged.

Air Purger / Air Scoop Installation FAQs

How do I release boiler pressure back to operating level after installing a new drain valve?

I need to install a new boiler drain valve on my Burnham (gas hot water) boiler and, as I do not want to drain the whole system, I plan to isolate the piping loop into and out of the boiler (close the relevant valves) and drain only the minimum amount of water out of the boiler to permit removal of the existing defective drain valve and install a new one.

My question is this: when I refill the boiler, will the Maid O' Mist 67 auto vent near the PRV eliminate air which enters the boiler with the refilling if the cap screw is left in the open position, or do I need to depress the Schrader valve beneath the cap to purge the air until the boiler is up to 15 psi?

Or is there any other simple way of eliminating air before cranking up the boiler and circulating through the radiators.

I'm trying to avoid having to purge air from individual radiators after this simple valve replacement. Thanks for your help. v

Reply by (mod) -

You might find it more effective to release boiler air through the relief valve until you start to see water discharge there.

That will fill the boiler and vent air much more rapidly than through the tiny air vent that you're describing. What you got the boiler nearly filled and most of the air out the remainder might vent out through your air scoop and air vent as you described.

by Greg

Thanks! I was a bit reluctant to disturb the PRV but will try it that way.

Reply by (mod) -

Greg,

Indeed you're correct to be careful about the pressure temperature relief valve.

The risk would be that you open it and it spits out a piece of an internal washer or gasket and then continues to leak.

We've written articles about dealing with that problem but my best suggestion is that if you have trouble with the valve you can post a comment or contact me directly by email using the page bottom contact like I'll be glad to give some advice.

Watch out: if the pressure relief valve has been un-touched for years you may open it and it will refuse to close properly. If that happens, just replace it with one of the same capacity rating.

Plan to add an air scoop when replacing my boiler expansion tank

I will be replacing my older Amtrol EX- 30 Hydronic Expansion tank and would like to retrofit it with the combination Package that includes an Air Scoop and Air Vent.

Since the Air Scoop is threaded cast iron I need to obviously sweet on a couple of copper Male Adaptors onto the pipe so I can in turn thread on the Scoop.

My question is: can I thread the Male Adaptors into the Scoop and then solder the Adaptors to the existing pipe?

I am unsure if there is anything in the scoop that may get heat damage or perhaps I will not get a good thread seal since any Teflon tape, etc. may get burned up in the sweating process.

I suppose the other choice is to install a Union, but in a number of pictures I have seen on what look like retrofit jobs, I do not see any Unions. Any advice is appreciated. Thanks On 2016-02-18 by Bill

Reply by (mod) -

Very good question, Bill.

I would take a look at the paperwork that comes with the air scoop. They'll warn you about heat damage concerns during installation. Let me know what you see.

by Bill

I have read the instructions on line and there is no indication about installing other then position: This Way Up, Flow This Way. If was a new system install, no issues b/c I could put the Adaptors on 'stubs' coming off the Scoop that go to the next fitting.

But retrofit? When I actually get the Scoop, I'll inspect, but even if 100% cast part, still concern over the thread sealant getting burnt if tread first, solder second. Have to rip it apart if it leaks... Of course I have head of lots of concerns over leaking Unions as well... So hoping someone may offer a 'trick of the trade'..

Reply by (mod) -

OK so when soldering, to protect equipment or devices on the hot side of the joint, wrap a wet rag around the protected device close to the fitting being sweated.

by Bill

Danjoefriedman, thanks and that is a good route to go if nothing else pops up as a good trick. I like it better than adding a Coupling (total of 3 solder & joints vs. 2)

Where should the water supply for my boiler be going to?

Where should the water supply for my boiler be going to? Currently the water supply goes to the boiler system return, the same port that all my zones return to.

water supply --> ball valve --> backflow preventer (Watts 9DM3) --> boiler autofill valve/pressure reducer (Taco 329-3) --> boiler supply

But as per the boiler manual, the Spirovent air eliminator manual and a few things I've found on your site and the internet, the water supply should be going between the bottom port of the Spirovent air eliminator and the expansion tank, the boiler system supply.

Is the current condition bad? Should it be corrected? On 2015-03-26 by Mosley

by (mod) - Spirovent air eliminator installation instructions

Mosley I'd need to see the system and its piping to have a confident opinion but you're probably OK. Often the installer will put the feed where it's convenient from a plumbing view. The sequence you described is pretty standard.

The Spirovent air eliminator installation instructions show a sketch with the water supply incoming at a tee between an expansion tank and the bottom of a vent at the boiler.

But that's not as critical IMO as the company's remarks that pertain specifically to the Spirovent location itself:

"The Spirovent Junior Air Eliminator should be installed at the point of lowest solubility in thesystem: that being where the temperature is the highest (i.e. after the boiler and/or heat
exchanger) and the pressure is the lowest (i.e. before the pump suction), as pictured in Figure 1below.

As with all hydronic system piping it is recommended to have the expansion tank
connection to the system on the suction side of the pump or circulator. " - www dot spirotherm dot com

Air Vent Atop the Air Purger Device FAQs

Should the air purger on top of the taco air scoop remains open or closed?

Should the air purger on top of the taco air scoop remains open or close? Feb 17, 2014) Joe

Reply: leave the air bleeder valve cap loose unless it's leaking

Joe,

Referrring to the AIR BLEEDER VALVE itself, mounted on top of your boiler's air scoop or air purger,

unless the air bleeder valve is leaking water we leave the cap loose or unscrewed a turn or so on most models; there are a few air purge devices that have more precise outlet controls. And some work with no air bleeder valve.

Tell me how to change the air vent on my boiler's air purger

How can I replace the float type air vent on top of the air purging device at my boiler? (Feb 18, 2014) Anonymous

Reply:

Anon:

To change an air vent or purger the steps required depend on what device is being replaced and where it is located.

At the top of this page under the article title you'll see a link to a closely-related article: AIR BLEEDERS - reading there you'll find a series of details on where air bleeders are located and how they are repaired or replaced.

For an air-scoop device like the ones discussed in the article found on this page you would have to shut down the heating system, let the system cool down, drain it, and use normal plumbing procedures to remove and replace the old air scoop device from the heating system piping.

Following replacement of a device like this one that requires draining the heating system piping (it's not necessary to drain the boiler or other components that are LOWER than the air purger/air scoop) you will have an air bound heating system so it will usually be necessary to manually force air out of the systems. InspectApedia sports articles on several methods to do that - fixing AIRBOUND HEAING SYSTEMS.

For just replacing a simple air vent like the ones at AIR BLEEDER VALVES it is often possible to work carefully, removing and installing the new unit with just a minimum of spillage, and without having to drain the system, though letting it cool is important to avoid getting scalded, and dropping system pressure can make the squirt and leak problem more manageable.

Will the Air Purger (Air Scoop) Work as a Check Valve to Allow us to Change a Zone Valve?

We need to change a zone valve. We can isolate one side of the zone valve with a valve will the air purger work as a check valve to isolate that from the other side? Or do we have to drain the whole system? Oct 9, 2014) Anonymous

Reply: no

Anon

Not for air purgers I've seen. That valve does not include a shut-off in the water line.

Sometimes a flow control valve at the boiler can be closed to act as the second shutoff. But

Your plumber may need to install a second shutoff, or may need to drain and re-fill the piping, purging air after that