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  1. #1
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    Water pumps and air locks

    trying to get me an edumacation on water pumps and air locks.

    Someone made a comment to me that we could eliminate the ongoing issue of getting an airlock daily on their system by putting in a larger pump to just, force its way through the air lock. its my understanding that this is not how that works, but since im no plumber or expert on moving water i was not willing to say either way.

    attached is a picture of their system.
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    what happens is when the pump shuts off (circle at bottom) all the water drains back into the tower basin. (They know the check is bad but that was not the conversation.)

    the air lock happens where the pipe is above the chiller and then runs 80 or so feet then drops down to the top of the tower. to me that is a pretty substantial air lock. were not talking just a little section of air were talking a good amount of 4" pipe.

    so my question is, is this guy correct in stating that throwing a larger/more powerful pump in will overcome the airlock? why or why not?
    In my experience, no it wont, but again, i usually just see little 1/2 horse recirc pumps not big equipment like this guy has.

  2. #2
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    Jan 2015
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    Somewhere making cold water
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    If check valve was working you wouldn't have air lock issue.
    Fix check and re group if issue continues. I wouldn't add bigger pump. JMO

    Sent from my SM-G920V using Tapatalk

  3. #3
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    Thread Starter
    Quote Originally Posted by WYLBEK View Post
    If check valve was working you wouldn't have air lock issue.
    Fix check and re group if issue continues. I wouldn't add bigger pump. JMO

    Sent from my SM-G920V using Tapatalk
    they know the check valve is bad and it is scheduled to be replaced. that was not the discussion. the discussion was, this (engineer) claims a bigger pump will just push the air out.

  4. #4
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    Possibly yes, why change the pump if the issue is the check valve. Seems like he wants to mask the problem not fix it.

    Sent from my SM-G920V using Tapatalk

  5. #5
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    Not to mention high point [auto] vents.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

  6. #6
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    Also if he changes pumps to be bigger he will most likely change the GPM through chiller which may cause even more issues.
    Good luck

    Sent from my SM-G920V using Tapatalk

  7. #7
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    I don't see any of the bleeders, for lack of a better word, that we used on a system we installed in a 9 story building. They purge air out of the pipes when the pump is not running.

    I don't think a bigger pump will overcome an airlock


    Sent from my iPhone using Tapatalk

  8. #8
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    These are all things that went through my head but I'm not smart in this area so I didn't say anything. I to thought it was a pretty silly statement to be made but I figured I was wrong. That's why I turned to the experts.

    I'm not involved in this work this was just a conversation I was having with a guy. I talk a lot and ask lots of questions cause I don't know a clue about chillers and big equipment. That's how this conversation got started. Sounds like they have lots and lots of problems this being one of them.

    I'll ask about Hoffmanns in the system.


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  9. #9
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    Water pumps and air locks

    Quote Originally Posted by jbhenergy View Post
    These are all things that went through my head but I'm not smart in this area so I didn't say anything. I to thought it was a pretty silly statement to be made but I figured I was wrong. That's why I turned to the experts.

    I'm not involved in this work this was just a conversation I was having with a guy. I talk a lot and ask lots of questions cause I don't know a clue about chillers and big equipment. That's how this conversation got started. Sounds like they have lots and lots of problems this being one of them.

    I'll ask about Hoffmanns in the system.


    Sent from my iPhone using Tapatalk
    Thats the word. Hoffmann. Thanks


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  10. #10
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    No it does not work that way. Just off the top of my head without knowing anything more about the system I have a couple question and thoughts for you

    Does the air problem happen immediately or after the chiller has run for some time. If it happens immediately the check valve and high point vent will fix the condition. To install a new pump you are there and can fix the check valve and new larger pump will probably need a different check valve. If it happen after the system has been run for a while you need to check if there is enough water in the basin as you are likely sucking air from the basin or in through another suction connection

    Larger (more HP) pump will require changes to the motor/pump base, possible changes is piiping connection sizes, a larger breaker, starter and posibble thermal overloads, possibly larger gauge wire (and conduit). If the flow get outside the range the chiller is design to operate at the impeller size will need to be reduced. If the GPM is sginificantly increased you need to be mindfull of the water velocity, you should not exceed 7 ft/second for copper or 10 ft/second for carbon steel or you will get erosion and wall thinning (eventually a through wall leak). Yes a higher head pressure will cause the air bubble size to become compressed more but what you will get is a foamy frothy water flow. If the chiller has a low flow water switch on the chiller it may not stay running. Does the chiller have some type of water regulating valve. If the GPM is increased the regulating valve should reduce the flow and you stay with the same condition

    Good luck

  11. #11
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    Thread Starter

    Water pumps and air locks

    Quote Originally Posted by Answer-Man View Post
    No it does not work that way. Just off the top of my head without knowing anything more about the system I have a couple question and thoughts for you

    Does the air problem happen immediately or after the chiller has run for some time. If it happens immediately the check valve and high point vent will fix the condition. To install a new pump you are there and can fix the check valve and new larger pump will probably need a different check valve. If it happen after the system has been run for a while you need to check if there is enough water in the basin as you are likely sucking air from the basin or in through another suction connection

    Larger (more HP) pump will require changes to the motor/pump base, possible changes is piiping connection sizes, a larger breaker, starter and posibble thermal overloads, possibly larger gauge wire (and conduit). If the flow get outside the range the chiller is design to operate at the impeller size will need to be reduced. If the GPM is sginificantly increased you need to be mindfull of the water velocity, you should not exceed 7 ft/second for copper or 10 ft/second for carbon steel or you will get erosion and wall thinning (eventually a through wall leak). Yes a higher head pressure will cause the air bubble size to become compressed more but what you will get is a foamy frothy water flow. If the chiller has a low flow water switch on the chiller it may not stay running. Does the chiller have some type of water regulating valve. If the GPM is increased the regulating valve should reduce the flow and you stay with the same condition

    Good luck
    ....... lol (idk I will have to ask)

    He said it happens in the spring and fall when the system is locked out on low ambient. So it gets cool at night and the pump shuts off and then the water flows back to the basin.

    Just text him and he said there is an air vent at the discharge of pump and high point of pipe. But they need a lift to get to high point so he does not know if it is working correctly.

    I google Hoffman and can that thing bleed a 4" pipe with that amount of air? Seams it would take a while.

    Waiting to hear back about the basin being empty.


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  12. #12
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    It appears by bigger pump he means increasing the GPM. That's not the answer but before that can even be considered you need to know how much water the tower can handle without over flowing. Too much water can also cause a plume of mist from the tower that can get everything in the area wet. The mist can also carry Legendella which can and has killed people. If the tower exit velocity is too high the vortex breaker may not be effective and air would be introduced into the system. Too much flow through the chiller can also vibrate the tubes and wear holes in them at the tube sheet supports.

  13. #13
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    Jan 2015
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    Crispin makes some pretty descent automatic air vent valves. Do a google search for an AL or DL series Crispin vent valve. I'd attach a brouchure but I'm challenged and have not figured out how to do that yet. Many places when the manual high point vent requires a lift or ladder they connect additional pipe and bring the manual valve back down to grade so the worker can vent without any climbing

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