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    air elimination (18 Posts)

  • dpframing dpframing @ 10:39 AM
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    air elimination

    I come to the wall again with hat in hand. There are some true pros on this site.
     IS it true that installing a Spirovent Jr. doesn't automatically insure 100% air elimination in the system? That is, I heard that the Spirovent will take care of microbubbles fine and will scrub out small bubbles as they come out of the water when heated, but it's not too good taking out the large bubbles trapped in the system.
    My case: I have a system with no air elimination  ( no scoop or any air venting at all). I try to bleed the air out of the system by closing a ball valve on the return to the pump and opening the hose valve (see pic).  After  sometimes 20 minutes of running cold water thru the system, I still hear large bubbling and loud gurgling sounds in the pipes. It seems that alot of air gets caught in the 3/4" pipe above the boiler that makes 2 or 3 right angle turns and doesn't run straight. The air is caught in the elbows. I thought of sweating out one of the regular elbows and installing a right-angle elbow with an air vent at the trouble spot, but this seems unorthodox. So now I'm thinking that a verticle-mounted Spirovent Jr. will take care of the air problem. I 'm an amateur so any suugestions to reverse water flow to move the air I cannot do. Is there a simple fix?
    This post was edited by an admin on January 14, 2012 10:43 AM.
  • Ron Jr. Ron Jr. @ 11:33 AM
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    Simplest fix ?

    I haven't installed a Peerless gas boiler in a while but I believe that 3/4 tapping the boiler feed and relief valve is in can be used as the air elimination tapping too . I would take add another 3/4 tee where the relief valve is , re-install the relief valve ( pointing up of course ) and add a automatic air eliminator on the top of the tee .

    To purge all the air out you need to keep the pressure up fairly high . We bleed the systems out at 20 to 25 psi . Always makes sure the relief valve pipe is pointed to a safe place . In a drain or in a bucket . What kind of heat do you have ? Baseboard ?

    We use the Spirovent Jr. on every boiler we install that doesn't have a separate tapping for a vent . To tell you the truth , the boilers with separate vents ports eliminate air just as well as the Spiro .
    This post was edited by an admin on January 14, 2012 11:36 AM.
  • billtwocase billtwocase @ 11:49 AM
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    echo Ron's words of wisdom

    Add another Tee where the relief valve is, and use the branch for your relief valve, and a Taco 400 with a 3/4 x 1/8 Bi reducing coupling and a Xclose nipple on top. It will help out alot. 
  • pardon_my_ignorance pardon_my_ignorance @ 3:47 PM
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    a couple "maybe" solutions

    from the picture you sent, it appears that your circulator is on the return side of the system, flowing into the boiler and the proceeding expansion tank. this set-up limits the pressure you can develop on the discharge side of the system, which will allow air to remain out in the field because it will not get entrained by the water pressure. once the air is entrained it can be brought back to a point of elimination ( air scoop w/ auto vent, other elimination devices, ,...), which should be located ideally at the lowest pressure point in the system, and if possible the hottest as well, for it is under these conditions that air will leave the water the easiest.
    By bleeding, you are also introducing fresh air into the system as it is entrained in the water. if you can't remove that air, it stays in your system, finds a nice little corner to hide, and blocks flow.  
    find and read "Pumping Away" by Dan Holohan for more in depth discussion. good luck!
  • pardon_my_ignorance pardon_my_ignorance @ 3:48 PM
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    a couple "maybe" solutions

    from the picture you sent, it appears that your circulator is on the return side of the system, flowing into the boiler and the proceeding expansion tank. this set-up limits the pressure you can develop on the discharge side of the system, which will allow air to remain out in the field because it will not get entrained by the water pressure. once the air is entrained it can be brought back to a point of elimination ( air scoop w/ auto vent, other elimination devices, ,...), which should be located ideally at the lowest pressure point in the system, and if possible the hottest as well, for it is under these conditions that air will leave the water the easiest.
    By bleeding, you are also introducing fresh air into the system as it is entrained in the water. if you can't remove that air, it stays in your system, finds a nice little corner to hide, and blocks flow.  
    find and read "Pumping Away" by Dan Holohan for more in depth discussion. good luck!
  • icesailor icesailor @ 4:36 PM
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    Elimination:

    I told you before, you can't effectively purge from the top of the boiler and send cold water through the system. You will NEVER know when the loop/circuit is purged.
    When I purge, I leave ALL the vents closed. I only install vents to keep nosey noses clean. Because your fill is at the top of the boiler, you can't purge properly. You are probably doing something wrong anyway. If you have zone valves, ONLY the zone you are purging should be open. The others MUST be closed.
    Put a washing machine hose on the drain of the water heater (right next to the boiler) and connect the other to the drain of the boiler. Close that yellow handled ball valve on the return below the purge drain. Connect a short hose to the purge drain and have a 5 gallon plastic bucket ready with the hose in it. Turn on the water heater drain and turn on the boiler bottom drain. Keep an eye on the boiler pressure gauge. If it hits 25#, close or slow the boiler drain at the bottom of the boiler. Make sure that the only zone valve that is open is the one you want to purge. Wait for the water to get hot. Leave the hose in the water in the bucket. When the air comes, it will first bubble. After the bubbling stops, the water will be getting warmer. After the bubbling stoops, and you still have at least 20# in the system, and you have shut off the hose on the bottom, feeding cold water to the boiler, open the yellow handles ball valve. Hold your hand on the copper pipe. You should feel the pipe getting hotter and cooler until finally, the pipe is very hot. It is purged.
    I installed a Spirovent ONCE in my life. When I went to drain the house, I blow out the system with air. The Spirovent leaked air faster than I could pump it. So, I put a 1/2" Black coupling and a 1/2' black plug in the air port. I have never taken it out. I never get any air.  
    Make sure that your Extrol tank is working properly. I'll almost guarantee that it has failed. It isn't working properly.
    The only way I see air getting into systems is through automatic air elimination devices. I now close ALL caps when I'm done. If they leak, I close them with pliers. n my own house, I got tired of changing #400 vents. I never had an air problem. And I still don't
  • Ron Jr. Ron Jr. @ 9:09 AM
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    Wrong , Ice .

    We pipe our PRVs into the top of our boilers quite often . As well as many other pros here . Most boiler manufacturers recommend this practice .

    I never had a problem knowing when the system is fully purged .

    We use Spirovents on boilers that don't have a separate tapping for air elimination . Our company installs hundreds of them a year . I haven't heard of any of these vents introducing air into a system . I agree that if you fully purge a system a Spirovent really isn't needed . But there's too many boilers out there piped wrong for air elimination . There's problem jobs that get air bound every year and a simple 1/8 inch air can changeout ( and leaving it open ) solves the issue . But if keeping the means of auto air elimination closed works for you , more power to ya !
    This post was edited by an admin on January 22, 2012 9:18 AM.
  • icesailor icesailor @ 5:02 PM
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    Air Elimination:

    You can feed a boiler in whatever way floats your boat.
    My comment was to a homeowner who was having a problem purging his system. I told him to put a double hose connection from the water heater to the bottom of the boiler and purge through the boiler. When the bubbles came, and the water got hot, it was purged.
    I'm continually in awe of all the old systems I've seen, installed and worked on that were piped wrong. That never had an air problem, never had a purging problem,  and gave or are still giving years and years of dependable service.
    How far have we come.
    All those improperly placed in-line circulators on the return that went for years and years with no complaints or leaking bearing assemblies and all those properly placed in-line circulators on the supply and bearing assemblies that lasted three years, hopefully. Thank God for wet rotor circulators, No wet seals to leak.
    How far we have come.
  • Paul48 Paul48 @ 11:28 PM
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    Pardon me

    You don't pump away to develop pressure.You pump away to eliminate pressure drop on the infeed side of the pump, that would allow the air to seperate out of the water.
  • icesailor icesailor @ 7:06 AM
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    Concepts:

    I know all the concepts.
    I've just observed more air problems in improperly piped systems that "pump away" than I have ever seen in a properly piped system that has a circulator on the return. And old in-line circulators on the supply (like B&G Series 100 and Taco 110's) were always puking water out of the bearing/seal assembly. The only thing that made it better was wet rotor circulators.
    And a HUGE percentage of Extrol type tanks are grossly undersized for their application. I've seen #15 Extrols on cold start boilers filled with Anti-freeze. I don't care where you put the circulator, the installer didn't read or follow the manufacturers recommendations for the install of the expansion control tank..
    If you live on the edge, and ride your dirt bike on the ridges of life, put them on the supply. If you ride on the road in the valley, I don't think it makes all that much difference if it becomes a matter of convenience. And moving a circulator that has been in place for 30 years on the return to solve a problem like a weeping PRV that started a month ago, is purely ignorant troubleshooting. And you will need to make some lame excuse for what you will do next to solve the still leaking PRV.
    Been there, done that, far too many times. Or, should I say, Seen that, Fixed that, Done.
    It's like my oil burner work. I get a new challenge, and the burner is running like crap, the first thing I do is check what the manufacturer recommends for that applicatiion. over 90% of the time, someone took a flyer and put something totally unsuitable in. I change it to the manufacturers specifications and start from there. People think I'm a hero. I'm not.
  • icesailor icesailor @ 7:36 AM
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    air elimination:

    Pardon me, but in 40+ years of piping and TroubleShooting'ing, the only time I have seen that happen (and that is only recently) is when the circulators are on the supply, and the system is piped too small, and the boiler is hot. Then, the air takes off. The float vents with loose caps, crud up and suck air when the system pressures change or for any other reason.
    Have you ever put tridicators on the supply and return of a boiler  or pressure gauges on either side of a circulator to really see the differential pressures? I've done it quite often. It's interesting to see if the head you planned on was 10# and turns out to be 5#. Or the inverse, your 10# head turns out to be 15#.
    How would you know.
    And like I said before, I was trying to tell someone how to purge his system an easier way, the way we used to do it or fill systems before the introduction of fast fill by-passes on fill valves.
    You ever fill a system by yourself that had radiators on three floors and the boiler is in the cellar? You pump the system with water until you get 25# PSIG. Run up to the third floor and start venting. You go to the second when the third is done. When the air pressure on the second floor is getting down, you hike it on down to the cellar and pump it up again to 25+#. Go up to the second floor and finish and do the first floor. By that time, the fill valve is giving enough pressure to finish the first floor.
    I have worked alone for over 20 years. I'm not hiking around for no reason.
    Every system I run into, I can figure out a way to purge it of air without ever leaving the boiler unless it has radiators. I still pump it up.
    At my age, I'm lazy. But smart, I like to think. I don't have the luxury of sending a "helper" to the third floor and wait for the pressure to get up there.  
  • Ron Jr. Ron Jr. @ 2:13 PM
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    I forgot all about this thread

    I was responding to your first sentence .........

    " I told you before, you can't effectively purge from the top of the
    boiler and send cold water through the system. You will NEVER know when
    the loop/circuit is purged." . I agree it's easier to know when a boiler is purged using hot water . I didn't know the " you " was specifically for the OP . If it was a general " you " I'd have to disagree with you .

    I've had to do that hose to the heater trick many a time too . Usually with an old PRV without a fast fill .

    I've also seen many a boiler piped wrong that have NO air issues whatsoever . Running for half a century or more . I've also piped boilers exactly to spec and have circs get airbound and burn out . But by and large I believe these systems work perfectly fine because of a simple 1/8 inch air can , open and working properly .
  • Paul48 Paul48 @ 11:20 AM
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    and the anwer is.........

    Try the Taco 400,it's the easiest. If you still have problems, add the spirovent.
  • MikeL MikeL @ 9:13 AM
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    I dont know ALL the concepts...............

    dp: I would never recommend using a water heater drain cock as a source of a high pressure purge connection; most water heaters are not maintained properly and you definitely don't want the minerals and sediment that accumulate in the bottom of the tank in your heating system.
      I read Dan's book " Pumping Away " in 1994 and have been doing so since with spectacular results. I suggest that if you don't want to move the circulator, at least move the feed valve to the place where the expansion tank is connected and add a Spirovent or equivalent.
  • icesailor icesailor @ 9:11 PM
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    Air Elimination/Purging:

    What did I miss?
    Someone come here with a problem getting the air out of hos system? And it seems to ma that his problem was that he wasn't doing it properly?
    He posted a picture of an older installed boiler with all the piping in place. Except, to some, the circulator isn't where they like to see it. The system must have worked at some time. Like when it was installed. Some want to re-pipe the entire system to get rid of the air. Re-piping the system isn't going to get rid of the air problem of no flow in a zone. His description of how he did it and couldn't get flow showed ME that he wasn't purging the zone properly. As I read it, it was only one zone. I didn't see anyone else here tell the guy a way or a better way to purge the system.
    I've seen systems that were so screwed up, I couldn't ever imagine that they would work. But they did and worked well.
    You know what happens to me regularly? Someone calls me up with a problem with a zone isn't working. I ask them, did it ever work? They answer in the affirmative. So, I go for a look. Sometimes, they may say that something needs to be changed, more often, they say nothing. I look at it. I go out to the truck and get a 5 gallon bucket and a double hose. I give it a quick purge and after the bubbles etc, "All Set". Oh. well, are you sure? Don't we need to change some piping? Not really, why?
    Sometimes, they tell me that someone else told them they needed to re-pipe the whole system because it is piped all wrong and they might as well replace the boiler while they are at it.
    The real problem was that the Extrol tank had no pressure in it, the fill valve was shot and only holding 5# in the system, and there were auto vents upstairs letting air into the system.
    Guess who gets credit for fixing the system and sells a new 9-11 PRV Backflow and Extrol tank.
    How did we go from a zone with air in it to re-piping a system?
    I sure don't know.
  • bill bill @ 9:42 PM
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    This poor guy!!

    I remember this. Originally, it was an air problem. Then Mr. Ice and ME get into it over pumping here and pumping there? Who knows?? I think we all should fly over to this poor guys house and fix the damn thing!
    This post was edited by an admin on January 24, 2012 9:47 PM.
  • dpframing dpframing @ 12:42 AM
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    Great

    Ok Bill. Thanks. When are you flying in? I'll pick you up at the airport.
  • rick in Alaska rick in Alaska @ 2:12 AM
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    purging zone

    Icesailor has it right. The only way to properly purge this zone is pumping in to the bottom of this boiler and forcing it out the return line drain after closing down the return line.
     If you don't like using a water heater as the purging source, you can use the method I use which is by using a transfer pump. I will fill the bucket partially with water and then pump this water through the system and then have the return hose dump back in to the bucket. This ensures I can also get all bubbles out by filtering it through the water in the bucket. Let the pump run for a bit until no more bubbles show up in the water, then close the valves and you are good to go.
     Rick
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