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Reverse Return balance question

Attached is a drawing of a reverse return system. Notice that I've shaded in Green the section of return piping after it passes the last radiator. By the way, I am designing a reverse return system with the goal of creating a balanced system. What I don't fully understand are the factors that impact the balancing. More specifically, notice I've painted in green the return run after it passes the last radiator. This section of the return is quite lengthy and makes the total return run quite a bit longer than the input run.

Very specific question, therefore, for the pros: Does that added length of return (colored green) create a system imbalance simply due to the fact that the total return run is longer than the total input run?

What I REALLY need is a crisp definition of what constitutes a Balanced and and Imbalanced reverse return system. I've spent many hours searching the internet and have come up empty.


  • Gordy
    Gordy Member Posts: 9,546
    edited October 2013

    You are planning on using trvs, or have dissimilar convectors then reverse return is not going to be applicable, or shall I say give you the balancing it is noted for..

    Two pipe reverse return works best when loops have similar radiators, baseboard, or what ever type of convector you are using . When you start to mix things up two pipe reverse return is not going to be self balancing.

    The object of reverse return is to get the same distance traveled from the boiler to each radiator to take place.

    So i see you are using TRVs what's the point they will throttle each radiator at different times of demand.

    I'm not really seeing the advantage for the pipe and labor invested to be honest.

    Buy Dans book pumping away it is clearly explained in there along with other piping practices. Not selling the book it's just well written buy an expert our host.
  • Tim_Hodgson
    Tim_Hodgson Member Posts: 60
    Your piping will be balanced

    since the TRV's are restrictive to flow. Gordy is correct that the reverse return piping is an added expense with little advantage. Your pump probably has more capacity in GPM  than the TRV's will allow. The first 3 TRV's will restrict the flow so there will be flow available for the last radiator. If you have already installed the reverse return piping, that is fine too.

    Best regards,

    Timothy Hodgson
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