American Air Purger: Clever or Just plain Wrong?

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Old 01-21-08, 04:22 PM
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American Air Purger: Clever or Just plain Wrong?

Second season in new (old) house and I am trying to understand the heating system. Reading these forums has been interesting and educational.

I have some air in the system so I have been exploring the system and I have a question.

I am looking at the plumbing of the Air Purger.

The top of the Air Purger where an air vent would be installed, instead there is the expansion tank, pressure reducing valve, and water supply.

The bottom is just plugged off.

Reading up on the air purger, it this seems to be installed incorrectly, but I wondered if somehow this was a clever trick?

The Boiler has an integrated air vent and I have some air vents on the return side just before the circulators (yes the circulators are on the return side) so some air removal should be happening along the way.

I found the vents on the 2nd floor baseboards but they leaked water after I retightened them and caused some grief to stop so I am leaving them alone for now.

For now I am curious about the Air Purger connections.

Any comments?

http://home.comcast.net/~mikenews/IMG_0339%20zip.jpg
http://home.comcast.net/~mikenews/IMG_0338%20zip.jpg
http://home.comcast.net/~mikenews/IMG_0337%20zip.jpg
 
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Old 01-21-08, 04:32 PM
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That's an interesting way to pipe the air separator and it totally negates any good that it may have served.
 
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Old 01-21-08, 05:15 PM
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Isn't that the silliest thing I've seen ? hmmmm, close !

Back in the olden days, when they used the large steel compression tanks, they would have been piped to the top of the air scoop, just like that. Reason being that you wanted the air that was caught to travel up the pipe and end up in the tank.

The way that one is piped it is doing nothing more than serving as a very large TEE fitting !

I doubt that the autovents in that other pic are doing much in the way of ridding the system of air either.

Looks like a pretty easy fix though... in that horizontal run of pipe, install a Spirovent to the right of the boiler. Get rid of the cast one that you have now. Hang the tank off that, and pipe the make-up water at that point.

You actually could re-use the existing scoop if you wanted to, just move it over, put an auto-vent on top, and hang the tank off of it, along with the make-up water.

When you re-do it, add a ball valve between the tank and the system so that you can isolate the tank for service when need arises.

Where's your circ pump ? I wouldn't mind seeing that part too ! I really dig the 'artistic' nature of those two air vents ... such beautiful symmetry !
 
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Old 01-21-08, 07:18 PM
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American Air Purger: Clever or Just plain Wrong?

I could see the logic of sending the air to the expansion tank as the potential clever part ... just needed to hear it from somebody else.

Originally Posted by NJ Trooper View Post
Where's your circ pump ? I wouldn't mind seeing that part too ! I really dig the 'artistic' nature of those two air vents ... such beautiful symmetry !
Here's some pics of the circ pumps. They sit just below the "artistic" piping for the air vents.

http://home.comcast.net/~mikenews/IMG_0326%20zip.jpg

4 zones. 3 grundfos and 1 taco

1 - first floor, 2 loops, 1 autovent
2 - second floor, 2 loops, 1 autovent
3 - bedroom over garage (has an autovent too, just up higher)
4- kitchen / utility room "add on" with the taco (no autovent)

My very first thought was to add zone valves on #1 and #2 and add the additional thermostats.

http://home.comcast.net/~mikenews/IMG_0353%20zip.jpg

But after reading the forums I am not sure I should mess with what is basically working and instead focus on venting (and autoventing) for now instead.
 
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Old 01-21-08, 07:50 PM
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Originally Posted by Miken1799 View Post
I could see the logic of sending the air to the expansion tank as the potential clever part ... just needed to hear it from somebody else.
.
Yeah, but... it won't work with the diaphraghm type of tank! That's what's silly about it .

I wouldn't change to zone valves ...

That return manifold has me a bit confused though! If I'm seeing this right, your 'manifold' looks to be maybe 1-1/4" pipe ? then, the pipe that leads into the boiler is what, 1" or maybe smaller (pics can deceive pipe sizes). But what puzzles me is why is it reduced in size at that point ? That's a bit strange. Your system looks very 'organic' ... as though it grew in stages to what it is now.

I agree... take care of the 'issues' and let the rest continue to work until it's time to change out the boiler. Then, rip it all out and start fresh.
 
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Old 01-22-08, 11:31 AM
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American Air Purger: Clever or Just plain Wrong?

Thanks NJ Trooper

That all makes sense.

I think the manifold is a larger pipe (Hammond Valve 606 #2) and it reduces to 1 1/4" which is what the Weil-McLain VE-6 wants on the return side.

http://home.comcast.net/~mikenews/IMG_0354%20zip.jpg
http://home.comcast.net/~mikenews/IMG_0356%20zip.jpg

The original installation was in the 1960's and may have had a large stainless tank (or just an old schooler doing things the old way). Either way I now understand the air scoop is not effective as installed in the current configuration.

The current boiler (Weil-McLain VE-6) was probably installed in the 80's as best I can tell, and may have required the reducing connector as the original boiler used the larger pipe. The 4th zone may have been added at that time or a little after that when a kitchen remodel was done.

How long this boiler will last is a good question!
 
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Old 01-22-08, 04:49 PM
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Kinda what I suspected, that the pics weren't showing the scale of the pipe ... the 'manifold' being larger is fine ... nothing wrong with that.

Probably right about an old tank being there, but I doubt stainless. They were usually just plain old steel, strapped up into the rafters. I'd guess that when they changed out the boiler, they disposed of that and added the 'modern' tank.

You could get another 20 years out of that boiler if yer lucky!
 
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Old 01-22-08, 06:22 PM
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Originally Posted by Miken1799 View Post
Either way I now understand the air scoop is not effective as installed in the current configuration.
Howdy. Just to further emphasize your point, in the current configuration the air scoop is not doing anything to remove air.

At the best, it's not doing anything bad.

At the worst, it is still deflecting air bubbles up into the piping going to the expansion tank and autofill, where it is accumulating because there's nowhere else to go. I suppose in a far-out scenario that piping could fill with air and thus the piping itself, in addition to the expansion tank, is serving as the expansion tank. Not sure if that's actually possible, but if I think like an air bubble, I could end up there. Never seen anything quite like this.

An example of an "official" way to pipe the fill and tank is shown here:

http://spirotherm.com/docs/installation/JrIOM-A.pdf

(but ignore the part about the "spirotop"). You have a perfectly good lower connection point available. I'd consider redoing the fill and expansion piping, and using an auto air vent in the proper location on the separator. Then you can isolate or remove the other air eliminators. They look old, leaky and are in about the worst locations to eliminate air anyway. One of them (far right of photo 0353) appears to have its little butterfly/gate valve closed, too.
 
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Old 01-22-08, 07:18 PM
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I would strongly suggest eliminating those auto vents on the return. Never put auto vents on return lines when circ's are mounted on the return. Initial start could suck air. Auto vents should only be on the return side and please no auto vents up in the system.
 
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Old 01-22-08, 07:35 PM
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Originally Posted by rbeck View Post
Auto vents should only be on the return side and please no auto vents up in the system.
rbeck, can you elaborate a bit on your last post ?

You said first that the auto vents should never be used on the return, then you said they should only be used on the return ?

I'm confused !
 

Last edited by NJT; 01-22-08 at 07:58 PM.
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Old 01-23-08, 04:40 AM
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I think in the latter he meant only on the supply side.

When not pumping away from the PONPC, air vents on the inlet side of circs can serve as "air letter-inners" rather than "air letter-outers" because the differential pressure for circulation is achieved by large negative pressure on the inlet side. Basically sucks air right through them. Don't ask me how I know....
 
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Old 01-23-08, 05:58 AM
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Sorry bout that. Yes, only on the supply and only at the air seperator. That is what happens when you don't proof after a long day at the AHR show.
 
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Old 01-25-08, 05:06 PM
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Thanks for all of the feedback.

What looked like an impressive installation to an amatuer appears to be frought with bad design.

Circulators on return
Autovents that add air instead of removing
Main Air Purger with the expansion tank on the vent

I'll wait to the later ion the season and try to address a few of these.

Thanks gain.
 
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Old 01-25-08, 05:30 PM
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C'mon now, it's not that bad !

Circs on return... how many years were they done that way? many more than I've been around... don't worry about it. While "new school" teaches to install on the supply side and 'pump away' from the expansion tank, the fact that yours are on the return ain't a show-stopper. There's MILLIONS of people out there in your court!

AUTOVENTS adding air ... at WORST ... MAYBE ... they might just not be doing anything ! either simply remove them, or screw the caps down tight on top. FIXED.

Yeah, that expansion tank setup is just plain silly ... but again, not really a hard fix ...

It's not a bad installation, really ...
 
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Old 01-25-08, 06:27 PM
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I agree with NJ, that it is not a bad system by any means. Honestly, I think that upside down gate valve on the return manifold is the worst part that I can see.

Right now you could close those little "valves" under the auto vents on the returns. This would allow you to remove the auto vents and insert pipe plugs for now and this summer you can remove the "valves (I wonder if the auto censor will object to stopcock?) and insert the plugs. I wonder why those auto vents were originally placed there as I can't see them doing much good under circumstance.

Since you have the ability to valve off the system from the boiler you could re-pipe the expansion tank assembly to the bottom of the air purger and then install one of the vents you remove from the return in its proper place.

Or, like the Trooper suggests, just live with it until summer and then do the retrofitting.
 
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