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primary/secondary piping

hydronicsmike
hydronicsmike Member Posts: 855
in THE MAIN WALL
...Expansion Tank on Boiler Supply followed by a System or Boiler Pump, then the very closely spaced T's for Primary Secondary.

Which T comes first? Well, usually the Supply, then followed by return in flow direction.
However, it could be done the other way around (reverse injection maybe?).

Difference would be that the Supply on the Primary Secondary would have a slightly lower temperature as it is mixed with the Return off the same loop. Depending on the circumstances, this may or may not be desired or effective.

Hope this helps you at least a little bit.

Regards,

Mike

Comments

  • Brian Knorr
    Brian Knorr Member Posts: 3
    primary/secondary cirulator

    can anyone tell me if it matters which side if the expansion tank the closely spaced tees are located? Also, does it matter which if the boiler supply is the first or second tee?
  • Brian Knorr
    Brian Knorr Member Posts: 3
    primary/secondary cirulator

    can anyone tell me if it matters which side if the expansion tank the closely spaced tees are located? Also, does it matter which if the boiler supply is the first or second tee?
  • Empire_2
    Empire_2 Member Posts: 2,340
    Answer.,.,,,,..

    It would help if a comma or 2 were place in the sentance. I hade to read it 3x to sort of make sense of it. Please be a-little more detailed if you can...
    Thanx Mike. Pump away,.... Where is your secondary pump?
  • Weezbo
    Weezbo Member Posts: 6,232
    to me it has an observable difference...*~/:) and i use commas

    like i am in a coma:)
  • Brian Knorr
    Brian Knorr Member Posts: 3
    primary/secondary circulator

    I am sorry for not being more detailed. I have 5 zones using UPS15-58FC pumps on a header type manifold.The air purger/expansion tank are on the supply header, ahead of the pumps.The low mass boiler is piped into the header as a secondary loop right after the air purger/expansion tank but ahead of the zone pumps. Most diagrams I have seen show the secondary loop piped ahead of the air purger/expansion tank. Does it make a difference?
    I thank you for the responses but find it humorous about the grammar corrections, as I too, usually have to read most of the reponses several times to make sense of the spelling or sentence structure.
  • EJW
    EJW Member Posts: 321
    Grammar

    DON'T, WRITE, IN, CAPS, EITHER, CAUSE, THAT, MAKES, THEM, MAD.
  • hr
    hr Member Posts: 6,106
    Do you mean like this?

    Or do you have a way to show us a drawing?

    hot rod

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  • jerry scharf_3
    jerry scharf_3 Member Posts: 419
    My take

    There are a couple things. Since the idea is for the closely spaced Tees to be at the same hydraulic pressure, as long as they are close to the x tank, it doesn't matter from the pressure point of view.

    There's another part to the question that was mentioned. It is common for x tanks to be hooked up to the loop at the air eliminator. Air eliminators like to have the hottest water possible. I design the emitter loop to be primary (have the x tank) and with this you want the air eliminator after the close tees, where the boiler water has just been injected. To make the boiler loop primary, you then really want to separate the air seperator from the x tank, so the pump is happy (pumping away) and the air eliminator happy (seeing hottest water.)

    These are just my opinions.

    jerry
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