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I'm trying to get a handle on when you would use a balancing valve, why you would use one and how you would select and adjust it.
I don't have a specific problem I'm trying to solve I'm just trying to wrap my head around all the different aspects of a hydronic system. I have watched several of the Caleffi videos (thanks for those Hot Rod) read a bunch of stuff (couple of Dan's books) and it just seems balancing valves get over looked or assumptions are made about experience and knowledge.
Heres my example. I have a 100 feet of 3/4 pipe in a loop, for whatever reason I'm not happy with it.
So I decide to split it right down the middle and do a split loop with each loop being 50 feet. This type of setup should balance itself naturally since everything is equal.
In my mind if I change this to say a 70-30 split the natural tendency of the water is going to go through the short loop since it is the path of least resistance. Ideally I would throw on a balancing valve or some other restriction on the short loop which to the water will make the loop look longer therefore help force more water down the physically longer loop.
Am I understanding the purpose here of the balancing valve?
It's also a way to step down the GPM flowing through one area and in the example above it would send it down the other path. If you had a valve on both loops you could restrict the flow down to something like 3gpm per loop or set one to 2 gpm and the other to 4gpm depending on your needs.
How do you decide this is the valve for me? Do you select it based on the GPM you are trying to achieve? The Caleffi Circuit Setter comes to mind with it's handy gauge on the body. Use a valve where your ideal GPM falls somewhere in the middle of the valve specs so you can wiggle one way or the other if needed.
Measuring and adjusting seems like everyone wants you grab some expensive gauge set but in one of the Caleffi videos they mention a simple pressure gauge with a needle probe will suffice if you don't mind a little spray from the ports moving from one to the other.
You just have to find the differential compare it to the provided chart and adjust up or down to get the GPM you want.
Does all that make sense? Still fuzzy on the selection process.