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SpiroVent/Tank Location

bruce pirger
bruce pirger Member Posts: 111
Found a good contractor to install a Buderus boiler and system for my radiant. I will be placing the boiler outside in a separate building (insulated) for a variety of reasons (noise dominates) as I don't have a basement.

System will be primary/secondary, two variable speed injection pumps (two radiant zones, slab and stapele up), and DHW, controlled with Tekmar 363 (an additional controller for second loop).

Boiler will feed into "plumbing wall" through roughly 50' of 1" Wirsbo hePex (as well as return to boiler). 55,000 heat load...so 1" line with 8gpm no problems...

Anyways...here's the question. I have been planning to install the spirovent and expansion tank at the boiler, outside, along with the primary pump. The installer suggest placing the spirovent and tank inside the house after the 50' run of 1" hePex.

Is this OK? I like the idea of the tank at the boiler to utilize the boiler volume to help remove the air...and just assume keep the primary pump outside...although they are quiet. While pumping away refers to pumping away from the point of no change, i.e. the expansion tank, I also assume I gain by locating the tank immediately next to the boiler. Comments?

I'm running all the 1" hepex in conduit as well as the power/control lines out, so that's not a concern from their regard. Also, I can run the water supply out to the boiler as well.


  • Steve Miller
    Steve Miller Member Posts: 115

    Where is the make up water going to hook up at? It's best to tie it with a tee at the bottom of the Spirovent with another tee for the expansion tank and have the pump right after the Spirovent so you're pumping away. Ideally its best to have it close to the outlet of the boiler where air comes out of solution as water is heated. I think you'll be ok if you do it inside on your heat run tho.

    Steve M.
  • Steamhead
    Steamhead Member Posts: 16,728
    Only problem I can see

    is that if the hot water supply comes out of the boiler and then goes down to the underground conduit, air will collect at this point. Installing the Spirovent, tank and circ in the line where it comes out of the boiler will prevent this.

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  • heatboy
    heatboy Member Posts: 1,468
    Looks like two.....

    air seperators would be a good solution here. One on the high temp loop and one on the radiant panel. Not knowing the layout, I may opt to put the compession tank and make-up on the radiant panel if for no other reason than serviceability.


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    The Radiant Whisperer

    "The laws of physics will outweigh the laws of ecomomics every time."
  • Ben_3
    Ben_3 Member Posts: 71

    If the 1" line is servimg as your primary loop you could place it in either location with the pump pumping away from the tank. However you are right in wanting it in the boiler room. Air will come out of solution in the hottest part of the system, typically the boiler. With the tank, spirovent and pump in this room it will work better since most of the air will be dealt with there, instead of possibly making into the radiant zones. It will also allow you to set up a power purge on the boiler to make purging a snap. I believe the mfg. also suggests it be as close to the boiler as possible as well.
  • Steve Whitbeck
    Steve Whitbeck Member Posts: 669
    perger location

    I would put an amtrol air purger and air vent at the boiler. I would put the spirovent and the expansion tank in the house along with the water make up controlls. Put the least amount of piping as is possible at the boiler so that if you loose power or have a failure you have less to repair from freezing. Also I tend to run staple up at full boiler temperature for better heat transfer. It is rated for 180*
  • bruce pirger
    bruce pirger Member Posts: 111

    Thanks guys! I like the idea of having the spirovent at the boiler. The desire to put the expansion tank and spirovent indoors, I believe, is for servicability and also no need to have the make water run outside then...although this is not an issue for me to do....I'll put the aquapex in regardless anyways. Also the primary circulator would be inside...

    But, I do like the idea of putting in two spriovents...one at the boiler...one indoors with the expansion tank.

    Everytime I start playing with a few fittings, I have this HUGE urge to start putting it all together and do it myself....

    Thanks again for all you help! Bruce
  • heatboy
    heatboy Member Posts: 1,468
    Since you are using......

    a Buderus boiler, a spirovent on the boiler probably isn't needed. Due to the size and construction of the boiler, the vent on the safety header is all that you will need to vent the boiler loop. Works like a charm. Spirovents are drastically over-rated. I use them where and when I have to, but a plain old air scoop works just as well, if installed correctly.


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    The Radiant Whisperer

    "The laws of physics will outweigh the laws of ecomomics every time."
  • chris smith
    chris smith Member Posts: 39
    spirovent location

    if you live in the northern part of the country i might consider 2 loops, one glycoal with a heat exchanger located in the house that way you would not risk a freeze up if the power was out for a while, up here in maine we had an ice storm that knocked out power for many days, [ i live out in the sticks and lost it for 27 days ] most folks did with out for around a week, with a glycoal loop you would not have to worry about freezing up the 100' of pex in the ground or heating your garage to prevent the boiler from freezing, just a thought.

    chris smith

    paradise porter maine
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