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Eloy, I think the reason you didn't get a reply is that there's not enough information about your system to make any sensible suggestions. Some information describing the layout of your plumbing system or even some pictures I think would be helpful.

Seriously? That analogy is vastly more inelegant than my hot water solution, and to use your word, it's downright absurd. I built a system that met a defined requirement. I did it because I couldn't find a plumber that could do it. I didn't have the knowledge to properly engineer it and I came...

In this application head is what was needed to increase flow and that's why the pumps are in series. One pump per loop is what I had and the 13' of head per pump isn't enough to get the flow that I wanted. At the estimated 4.5gpm the differential pressure is 27' to 30' of head. This setup works...

That's right because as velocity goes up head increases disproportionately. That's why 3.5 - 4.5 GPM is the sweet spot for 3/4 pex. Great performance and no turbulence concerns. And like I said in my last post if I didn't already have these pumps I would use a Taco 0013 3-speed pump that handles...

For those that followed this thread I thought I would follow up and let you know where things have landed in my effort to find a sensible sweet between fast hot water delivery and not damaging my plumbing with excessive flow rates and turbulence. If you recall I used two Taco 006e3 pumps in...

1 x 150 is the longest. 2 x 100 give or take, and 1 x about 50'. But each loop operates individually and more than one open at a time effectively never happens.

1" pipe or whatever gets to 7gpm. I was talking specifically about 3/4 PEX nd neglected to say that. But the point is the charts assume something about the pipe diameter. So for your .03 or .04 per foot of pipe, for that to apply you need the right size pipe.

I made a mistake describing the results from the sizing calculator. I didn’t include fittings and valves. It’s 34’ of total head including that.

That factor of .03 assumes a gpm of 2.5gpm. You did make an adjustment for fittings but not for the higher gpm. I got very tripped up with this too and that 2.5gpm for circulation pumps I found is overly engrained as an assumption. Taco has a pretty simple sizing calculator called “DHWR” that...

I got tripped up by it too and

I see what it is and it's just a simple oversight. It's not the chart but using an invalid head number. You need to know what GPM to target to determine approximate head using pressure drop tables, and then use that head with the chart. So for 8gpm in 150' of 3/4 PEX head is 42' which is of...

Thanks for posting that. The point about the bacteria is something I hadn't thought about. Not sure it matters for hot water but I'll definitely think about it. Looks like the proper valves are around $100 each or a little more.

Nothing was wrong, it worked great. I just always wished for faster hot water delivery. I realized I could reconfigure the system to work with a common pump(s) and get rid of all the check valves since I had added the solenoid valves as a modification. And because I had three extra pumps I...

I think I see why you're asking that. He seemed to be referring to pressure drop tables rather than the pump chart which I think you are. According the chart using the 6.75' of head that you estimate definitely shows around 8gpm. But the pressure drop table says 42' of head for 8gpm in 150' of...

I spoke with with a Taco tech support rep this morning about my application and went through all the numbers. He confirmed that there is a startup ramp but it's just a few seconds and I'm over estimating it quite a bit. He also confirmed all the math was correct and the differential pressure...

I think we're finally on to something here that might explain things. There seems to be a startup ramp that hasn't been part of the equation. Water doesn't go from 0 to 8gpm instantaneously and I'll describe what I see in this application. Regarding expected pump performance you came up with an...

Yes, I figured out a while ago the .03 made no sense. My current estimate is .0525 with the two pumps. If I were maxing the speed for pex with one pump turned all the way up I would have hot water faster than I dreamed. But that's not happening so I'm thinking you're making an incorrect...

Where do you come up with 5' of head? Doesn't the differential pressures (4psi with one pump and 8psi with two pumps) say otherwise? My estimates based on these differential pressures are about 9' of head and 20' of head for one and two pumps. Based on that I estimate about 3.5GPM for one pump...

Thanks and I'm well aware of that. The hot water which is also softened doesn't get consumed in this house. I have a pot filler faucet supplied with city water for that.

John, here's some new differential pressure information below. But to answer your questions, Pumps are on MAX setting. Your comment about pro's not doing this sort of thing was why I did it myself. And one pump or two pumps I've VERY HAPPY that I did. You say nobody would do this but as I've...