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converting to pumping away/ cost effective?

Just a little intro. I have no training in hydronics. The extent of my hydronic education is from reading Dan's books. I was by a customer recently and while pocking around his basement I noticed that his hot water boiler has no air eliminator, a circulator on the return and an interesting compression tank set up. There are two pipes coming from the top of the boiler. One pipe is the main. The second pipe has the compression tank and water feed connected to it. If I understand this correctly this is the equivalent of placing the point of no pressure change in middle of the boiler. My question is if it is cost effective for the customer to move the circulator to supply, move the tank to the supply main between the boiler and circulator and to add an air eliminator. I am also interested in knowing which air eliminator  the knowledgeable wallies would recommend. The boiler is a40k unit with one zone on a small addition to the house. The customer complains of cold and of always hearing water running. I have thoroughly read pumping away. GREAT BOOK!  Thanks a ton.


  • Mike KusiakMike Kusiak Member Posts: 604
    What boiler and what type of tank?

    Is the compression tank a plain steel tank or a bladder tank? Some boilers such as the Burnham series 2 have a built in air separator in the heat exchanger casting, which is connected to a tapping in the top of your boiler. If a plain steel tank is piped into this top port it will serve to return air to the tank and prevent waterlogging. Of course, the air elimination will work much better if pumping away from the boiler, but even with the pump on the return the built in air separator is pretty effective.
    dont remember

    Thanks for the reply. I don't remember which boiler. The tank is a diaphragm type.
  • IronmanIronman Member Posts: 3,550
    This Setup...

    Won't work with a bladder tank since there is now no means of air removal. Someone probably replaced an old bladder-less tank without realizing they'd defeated the air elimination system.

    You must use an air separator with a bladder tank.

    If you've read Dan's books, you've gotten alot of hydronics education.
    Bob Boan

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

    is adding the air eliminator adequate or should i also move the circulator and tank?
  • Mike KusiakMike Kusiak Member Posts: 604
    Air vent

    You can first try attaching an automatic air vent to the top of the riser from the boiler where the tank is connected. The air that is now collected at the top of the boiler will now be vented.

    Do you really have an air problem or is it something else. What type of noise is the costumer hearing. Is it velocity noise or gurgling from trapped air?
    running water

    The customer describes the noise as a running water noise.
This discussion has been closed.


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