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Venturis in baseboard plumbing

PeterJH Member Posts: 1
My baseboard plumbing is old with lots of leaking copper fittings, so I plan to gut  and replace all w/ Pex. My question is: should I eliminate the venturis and go strait thru all baseboards? Second, is there a general design guide for baseboard system layout and plumbing? Why are venturis used instead of going strait thru the baseboard? Third, can I mix venturi and strait thru baseboard plumbing? thanx in advance for advice.



  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    Venturris are COOL...

    I designed them into my own new heating system (now 11 years old) when I built it. The one advantage to VT's is the fact that you can shut off baseboards/emitters in a given circuit without affecting the flow to other convectors. However, with that said, the pressure drop through the main increases significantly if any of the branch valves are closed.

    I have a mix of both, and it works quite well, but you must be aware of the pressure drop issues if side branch valves are closed. It requires a flat curved pump to insure proper operation.

    The other original perceived advantage of a venturi system was that it was done using one pipe, instead of two.

    Today, we have access to a non electric thermostatic bypass valve, which means you can have emitters in series, and if one shuts down, the flow bypasses it and goes to the next set of convectors without shutting the series of convectors down.

    Oventrop makes the 3 way non electric thermostatic bypass valve for baseboards.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
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