Air Purge Loop

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Old 09-20-14, 12:44 PM
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Question Air Purge Loop

is this a workable solution?
i need to install an Air Separator into an existing line on the supply hot side.
I have three riser pipes coming off the horizontal supply.
Two are for separate zone loops, the third is just a stub but that is the one closest to the supply riser so that gets supplied first.

Can I simply remove the end cap on the stubbed riser and replace it with a Tee
and then add enough horizontal piping at that level to install the Air Separator in its own loop?
If so, only 1/3 of the supply will will go through the Air Separator at a time. It probably wont be highly efficient but will it get out all the air over time?
This is the easiest way for me to pipe it.
 
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Old 09-20-14, 03:40 PM
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I think I have a better idea.
the supply riser is 24" from the boiler housing to the horizontal supply pipe that supplies the zones.
If I cut that pipe at 20" and put an Elbow there and then cut the pipe at 22.5" and put the return elbow there, I can route in the Air separator line.

Is there any minimum initial supply riser height I need to keep?
 
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Old 09-20-14, 04:16 PM
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I've been following but since folks have been helping have not replied... what I'm thinking though is that photos would really help us help you.

I try to visualize your descriptions but am unable.

Are you able to post pics?
 
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Old 09-20-14, 04:51 PM
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thanks Trooper, I follow your posts for some time now. always good.
sorry I dont have pics or a camera or a phone that takes pics.
its pretty straight forward.

hot water supply rises from boiler 25" and then turns into a horizontal manifold.
from there three feed risers to into their own loops.

I propose cutting into my vertical riser at the 20" and 22.5" marks and turning elbows perpendicular to the horizontal manifold so I have room to pipe in an air separator.
but that would reduce the height of the orignal supply riser so I was a little concerned.
but if I can do that, that would be the easiest cut in that I can see.
I dont really want to mess with the horizonal manifold.

thank you
 
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Old 09-20-14, 05:22 PM
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There ARE air removal devices that mount on vertical pipe...

VJV100 - Spirotherm VJV100 - 1" Spirovent Jr. Vertical Air Eliminator (Threaded)

Of course, if you've got a bought and paid for one that can't be returned, this might not be an option.
 
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Old 09-20-14, 05:23 PM
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I'm also thinking that it might make some sense to merge all your different threads into one...

What you think?
 
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Old 09-20-14, 05:50 PM
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yeah I tried to do that with my first post but all it did was look like I replied to myself.
if you have a suggestion on how to do it, I will do so.

Anyway, I measured and now I have to cut the vertical riser at 17" then I am making a 20" horiz then up 5" then back 20" , back to the main manifold and up to the zones. this way I can mount the air elim on top.
 
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Old 09-20-14, 05:57 PM
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You can't do the merging, has to be done by moderator... I can do... I'm just afraid it might get confusing with out of sequence and what not. Let me think about it some...

I sure wish I could see what you're working on...

It kinda sounds as if you are designing as you solder. It's always best to have a diagram of how you want to build it and work from that. You know, the 'big picture'.
 
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Old 09-20-14, 07:07 PM
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i made a drawing i think I attached it but maybe not.
the first image is the current system
the second is what i hope to do, but I have to cut into the riser at around 17" and that may not give enough vertical - or maybe it doesnt matter.

Solder how you go? not me - thats the last thing I do, thats why it takes me so long to do anything.

thanks again Trooper
 
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Old 09-20-14, 07:13 PM
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What make/model air separator do you have?

Some of them require (for best performance) at least 18" of straight pipe ahead of them.
 
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Old 09-20-14, 07:35 PM
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Taco 4900 Series Air Separators

i can go more than 20" out and back, I am just concerned about cutting down that boiler riser to 17" instead of 25" that it is now.
 
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Old 09-21-14, 08:48 AM
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The 4900 has no minimum straight pipe length requirements.

I am just concerned about cutting down that boiler riser to 17" instead of 25" that it is now.
Why? What are your thoughts that it might be detrimental?
 
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Old 09-21-14, 10:15 AM
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I just didnt know if there is some minimum vertical run that must come up out of the boiler before it starts branching to feed the supply.
I cant find anything on the internet on it so I guess there is no minimum requirement.

in creating this air eliminator loop, I will have to cap the bottom of the eliminator since I cannot hang am expansion tank below it. - no room.
I was thinking to add a valve on the lower line of the loop - going out,
then turn up, then turn back both with elbows,
then on the top line of the loop the air eliminator and maybe add another temp/pressure gauge which would be the third one, but I dont think here would be a good place since it is already close to the temp/pressure gauge on the boiler. My second one will be after the water feed reducer.
 
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Old 09-21-14, 10:39 AM
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I think I just figured out the best way to do this.
instead of isolating the line into an air purge loop using two elbows, I will use two Tees on the riser instead. that keeps the full vertical of 25"

Then between the tees I will use a globe valve and have that shut initially filling the boiler.
then throttle that open so only some part of the pipe goes straight up and the rest goes through the air eliminator loop.
(see attached)
 
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Old 09-21-14, 10:54 AM
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I think you are overthinking this whole thing.

I don't see the need for the extra valves.

The only downside to what you want to do is that the extra elbows will add a bit more 'head' to the system, but it is doubtful it would cause a problem... and it will look a bit whack...

There is no minimum riser height requirement on a water boiler... steam, yes, but water, no.

The purpose of extra pressure/temp gauges is why?

In a 'perfect world', your air sep would be on the suction side of your pump.

Where is the pump in relation to this?
 
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Old 09-21-14, 11:42 AM
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the valves can isolate the air eliminator if I need to take it out.
I figure I will need to add a hose bib at the far end, opposite the vertical valve.

unfortunately, as in the old weil mcclains, the pumps are at the bottom of the return line
so this supply is on the push side but this is the hottest water so maybe a good place to take the air out.
 
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Old 09-21-14, 11:46 AM
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instead of an air purge loop,
should I just put in a single tee and add the air eliminator and then a terminator
basically piping out 12" horizontally in total?
but that will disrupt the flow wont it?
 
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Old 09-23-14, 04:05 PM
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Question

I started piping the air eliminator loop with Tees as I described.
The eliminator has 1" female threaded. I plan to use pipe dope on the male adapter threads - any objection?

Also, I have no room to drop an expansion tank under the air eliminator but will place the tank elsewhere. Does that present a problem?
 
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