Generally, attempting to balance your returns with valves is going to be a loss in efficiency. You are far better off having all returns at 100% and having an imbalance than reducing the flow on the strongest return and reducing the total flow rate of all the returns in aggregate. However, to control deck jets, waterfalls and other features, valves are a must.
As for the number of return lines, having multiple lines is fine but you can accomplish the same thing with a single larger line too. 2x2" is about the same a 1x2 1/2".
Also, you can balance the returns by having a larger pipe between the returns. The reason returns end up having different flow rates is because of the pipe loss between the returns. Increase the pipe size and you end up decreasing the pressure difference between returns and evening out the flow rates. Not that balanced returns are all that necessary anyway.
Yes but what is your point? If you had had three lines of 1 1/2" pipe it would be about the same then. Pumps have a very wide range of operating points which is why the publish a head curve. All are valid operating points.I'm am by no means an expert in fluid dynamics here but doesn't a long run of large diameter pipe mean a lower pump pressure and higher flow rate? As well, don't water pumps have a flow versus pressure operating point where they are designed for a specific range or else they don't pump efficiently?
My real world example here would be my waterfall where the pump output is tied the a 3-way valve that selects between the 2-1/2" waterfall pipe and a 1-1/2" return. If I put the full pump on 100% to waterfall, the pressure is real low, the flow rate is high and the wet-head makes a lot if noise. If I mix the water so that there's some going to the single return line, then there seems to be enough back-pressure to make the wet head quiet again.
Either way will work fine. There might be a slight difference in head loss but I don't think it would amount to much.dumbcluck said:So what is a better solution here? Should I let him tee two of the 2" returns together and bring two 2" lines up to pad? Or just let him tie all three underground and bring it up once and be done with it?