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Air in hydronic heating system - How to bleed?

Hi everyone! My kid's bedrooms are making a pipe banging racket and it's getting worse. Suspect air in my pipes but don't know how to bleed my system. An hvac guy was here once when my wife was home and said that this isn't something that I can do myself. I can't believe that and was hoping to have the help of some folks here to do just that.

We have a gas fired furnace, with a couple of zones. Only my kids zone in particular, is noisy. It's served by a B&G series 100 booster pump/circulator that I circled in red below. There are shut off valves above and below the pump and a faucet right above it, which I assume is for bleeding the system. You'll see that there are also a series of shut off valves along the top of the photos.

What I don't know is:
1. what are the valves along the top for? if they're not the return line, then my system would seem very odd as it would seem the circulator is on the return side when I would assume it would be at the side of the source.
2. if i'm to bleed the system, which of the three inline flow valves do I have to close, there is one above the red pump, one below it, and another along the top (question 1 above, i'll have to guess which one serves my kids bedroom)
3. when I am bleeding just the circled one (2nd floor kids room), do I have to close off all the valves for all the other zones?
4. i assume that when I am bleeding the system, i would turn on the tap after lifting up lever on the regulator stepping down the municipal water flow to force the water through the system. Not sure if I lift that regulator control slightly or all the way?

photo IMG_3196.jpg

Thank you all so much. My wife and children thank you!!!

Some more photos for reference:

photo IMG_5643.jpg

photo IMG_8943.jpg

photo IMG_5544.jpg

Comments

  • IronmanIronman Posts: 4,570Member
    I see no hydronic expansion tank in your pics. Where is it?
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • IronmanIronman Posts: 4,570Member
    Do you have baseboard radiators?
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    edited November 30
    Thank you Bob. No baseboard, we have forced hot air so just have vents in every room. The expansion tank is on the other side of the heater.

    photo IMG_4393.jpg

    photo IMG_9996.jpg
  • IronmanIronman Posts: 4,570Member
    I'm not sure air is your problem. But to purge that zone:
    1. Turn the boiler off at the switch
    2. Close the ball valve right above the circulator.
    3. Close all of the other ball valves below the other circulators.
    4. Attach a hose to the boiler drain above the circulator and run the other end outside or to a drain.
    5. Simultaneously open the boiler drain and lift the bypass lever on the fill valve.
    6. Watch that the pressure doesn't get above 25 psi or the relief valve may dump.
    7. Once you've got a clear stream of water with no air discharging, lower the bypass lever first, the close off the boiler drain.
    8. Open all the ball valves and place the boiler back in operation.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    edited November 30
    Thank you so much Bob! You are a life saver. I wonder why you had originally asked about the expansion tank. That's where the pressure gauge is so perhaps its related to that?

    Most importantly, would you or anyone else possibly know what those ball valves are for that area on the upper right of my furnace in (blown up in 4th photo)? I wondered if I would need to close those valves as well? It would really help to understood in what direction my water flows through this system and what the relationship is between the bottom section where the pumps are and the upper right section. Thank you all!
  • IronmanIronman Posts: 4,570Member
    edited November 30
    Those are on the supply. You can leave them open while purging as long as you close the ones under the circulators.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • DZoroDZoro Posts: 477Member
    Make sure the pump drive assembly is intact between the motor and the pump.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Thank you both very much. DZoro, i'm not sure I quite understand your comment on the pump drive assembly.

    All the pumps are indeed fully intact, although I am having issues with an intermittent slow-blo fuse going associated with this same circulator for my children's room. I will set up a separate thread about that, as I have purchased a replacement b&g 100 pump. Thank you again!
  • IronmanIronman Posts: 4,570Member
    edited November 30

    Thank you both very much. DZoro, i'm not sure I quite understand your comment on the pump drive assembly.

    All the pumps are indeed fully intact, although I am having issues with an intermittent slow-blo fuse going associated with this same circulator for my children's room. I will set up a separate thread about that, as I have purchased a replacement b&g 100 pump. Thank you again!

    You need to get rid of the series 100 and go with wet rotor circs like the Taco 007's or 008's that are on there or a Grundfos ups15-58. The flat pump performance curve on the series 100 is not a good match for a fan coil. It also costs 5 times as much. It's 1950's technology.

    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Thanks very much for that insight Bob. I suspect you are right. You'll see that I already have two Taco 007-F5's in my system, for my attic and room above garage. I had asked an HVAC guy before and he said that the Tacos don't may not necessarily be direct replacements for these two other zones that heat larger spaces and require more gpm flow as opposed to head since they're for the 1st and 2nd entire floors.

    With that said, Grundfos would have been a better decision and perhaps a closer performance curve, but I do already have an extra BG 100 on hand that I purchased for (relatively) cheap on eBay. Live and learn...
  • IronmanIronman Posts: 4,570Member
    That's my point, the flat curve of the 100 falls off very quickly as the head increases. That's why they're not the correct pump for a fan coil which introduces more head than baseboards or cast iron rad's. The 15-58 will actually give more gpm than the 100.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Sigh... looks like it's a lot less expensive as well. Too bad I already bought the other pump. My home was constructed in 1998, so i'm surprised the B&G 100 was the original choice given the competition... I suppose B&G is the 800 pound gorilla in this space.
  • IronmanIronman Posts: 4,570Member
    You’re contractor probably had the mistaken idea that since it was physically bigger it was better.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • hot rod_7hot rod_7 Posts: 9,026Member
    The air purger you have is also 1950's technology :)

    Ideally it needs 18" or more of straight pipe upstream to even have a chance of doing air removal. Get as much air out in then purge, the air purger is intended to grab air that comes out as the water warms, so you need a good purger to complete and maintain an air free system.

    Assure the small air vent on that purger is working and you will probably get by.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Thanks @hot rod 7. Can you please help clarify which is the air purger? Is it the one above the expansion tank, or the 3 red ones on the supply side on the upper right of 4th picture, or the one near the bypass lever in photo 5? best.
  • hot rod_7hot rod_7 Posts: 9,026Member
    looks like this cutaway example
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • IronmanIronman Posts: 4,570Member
    The 3 red things are flow checks.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Wow, thank you all so much for this great information! Will let everyone know if i'm successful in eliminating the noise. Can't wait!
  • Alan WelchAlan Welch Posts: 103Member
    It's possible that there is an air vent on the air handler piping, is it easily accessible?
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Yes, it's easy to get to them. There are a few air handlers in my home. Here are the two associated with the noisy pipes.

    Above one child's room (noisiest):

    photo IMG_6756.jpg

    photo IMG_2579.jpg


    Above the other child's room (ok, not noisy):

    photo IMG_4000.jpg

    photo IMG_6173.jpg

    These look like bleeder valves, but not so sure what i'm supposed to do with them...
  • hot rod_7hot rod_7 Posts: 9,026Member
    Those are auto air vents, and it is good practice to have them at high points in the system.

    Its is also possible to pull air into a system with vents on a system where the circulators are pumping towards the expansion tank as yours is. If the problem started when higher head circulators were swapped in place of the series 100 B&G it could be those high point vents.
    What is the system fill pressure, the gauge on the boiler read?

    With low fill pressure and a medium or high head circulator pumping toward the expansion tank you may be experience a negative condition up high and pulling small air amounts in.

    If you get all air purged out, try closing the valve below, or tighten the cap on those high vents.

    Lots of air elimination on the system :), the purger, a vent on top of the boiler and vents on multiple air handlers?

    With proper piping, a single micro bubble purger at the boiler and a high point vent should be all that's required.

    But it would involve some repiping and component addition back at the boiler.

    We build a temporary fix part for vents that are or may be sucking air in, but alas it will not fit the brand of vents you have.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Thanks everyone for your help. I finally got around to trying to bleed the system late last night. I probably emptied 10 5 gallon buckets or so until I got too tired (there is no drain in my basement so I have to run each bucket upstairs and outside). There wasn't really any gurgling or bubbles that shot out during the process. I followed the instructions from @Ironman exactly so extra thanks for that.

    The water coming out was quite hot, so I wonder if I was simply emptying out the indirect water heater and never really getting to the water in those pipes? Should I have also closed the two ball valves to the indirect water heater as well or was that ok to leave open?
  • IronmanIronman Posts: 4,570Member
    Yes, the only valve that should have been open was the supply on the particular loop that you're bleeding.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • DZoroDZoro Posts: 477Member
    Shut off all other valves other than the one zone you are working on. When that zone is fully bled shut it's 2 valves off and continue to the next, and so on.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    Apologies for my ineptness to what should be a simple process.

    photo IMG_3196 3.jpg

    In the photo above, I closed 2, 4, 7, 8 and 9 (1 and 11 are closed because of a disparate leak issue).

    I left 3 open, and had slowly opened the bypass lever.
    Sounds like I should also have closed 5 and 6, but I'm thinking this would be a problem, as the hot water heater is the only way water is getting to the supply side?

    Based on earlier comments, the supply side is 12, 13, or 14 above and those remain open, but I don't see any pipes connecting the water main to that supply side, other than through the hot water heater.

    photo IMG_8764.jpg


    What I'm not understanding is how water gets into my system. If the water is coming from where 10 is, how is it getting into the system via 3, which is the return side? Is it by way of going into the furnace. So,... flowing BACKWARDS through my system to finally come out the spigot right above 8 (which is closed) on the return side?
  • IronmanIronman Posts: 4,570Member
    Number 11 and 12 are the only ones that should be open while purging that loop.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • SuburbanHomeOwnerSuburbanHomeOwner Posts: 18Member
    oh? number 11 has been closed for the past year. that one feeds another air handler that has a burst heating coil up in the attic (there are 3 up there). if i turn that one on, then my attic will flood so i don't think that's the one.

    the way i thought about it, was that for this particular air handler for my kid's room, the supply is either {12, 13, or 14} (see second photo in last comment) and the return is {3 and 8}.

    water supply looks to come in via 10, through 5 to the water heater, back via 6 and up to either {12, 13, or 14} for supply...
  • IronmanIronman Posts: 4,570Member
    I'm sorry, but between your pics and numbers, I can't tell which loop your on.

    Here's as simple as I can make it: close all valves except the one on the supply to the loop you're trying to purge. Put the hose one the boiler drain above the circulator and purge the air.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
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