Greenhouse Plumbing curiosity normal pressure?

[Shadow_storm56]

So around the farm there is a ton of repairs and matinance to do of various things. One recent thing is pump issues with the submersible pump in my resivoir that feeds the greenhouse. Recently replaced a failing pump but that's not what was the issue... If I had a full wide open valve way over in the greenhouse my gauges near it obviously drop close to 0. (Not a tap this is a large valve for other uses that I was using to test) Problem was over in the barn whare the pressure tanks and stuff are I would still maintain 50-60Psi.... 800ft away but a flat grade and a smooth heavy duty 1 inch well pump the entire way. So I want to add another offshoot into it anyways and had suspicions of a cluster of fitting near the pond that split for the drain line and to go up to the pressure tank. So I took the excuvator and dug near that, obviously I broke the line because my dad didn't see it fast enough but no issue because I was adding in a connection there anyways. So while it was apart I forced water both ways incase there was a blockage of some sort.....

Expecting no luck I put it back together and anticipated no change. Surprisingly there was a big change.... now if the far valve is wide open I drop to 40Psi at the barn and my flow reaching the end is higher. I went from not being able to water my one large raspberry field with just that pump to doing it easily.

Before the pressure at the greenhouse with the raspberries trying to run would drop to 20 or lower and be 90+ at the barn.... now I hold 40-50Psi at the greenhouse and 70 at the barn.

Anyways long story but is this normal now or am I seeing still a bit too much pressure drop? My guages on the far end are right before it enters the greenhouse system and splits in many directions. I keep thinking on a flat I should see the same pressure at both ends.... especially since it's one long smooth pipe with maybe 2 or 3 barbed joints.

What do yall think?

 

[GreensvilleJay]

'on the flat', pressure drop is based on the length of pipe, the size of pipe, the material of the pipe and number of elbows and joiners. Simply put,there is NO way you'll get 50PSI at both ends of a 100' hose, it's a 'physics thing'.
There are plenty of 'online calculators' you can use(try 2-3 to see if they agree ).

Now if you're going uphill, 1PSI will push water up about 2 feet, so 1/2PSi per foot. If you need to go up 50', pump needs 25PSI. If you want 40PSI pressure up there, set pump for 65 PSI (25 for rise, 40 for flow ).

re: 800' run. I'd have run a continuous pipe(no joints) with a fox wire.

 

[Shadow_storm56]

'on the flat', pressure drop is based on the length of pipe, the size of pipe, the material of the pipe and number of elbows and joiners. Simply put,there is NO way you'll get 50PSI at both ends of a 100' hose, it's a 'physics thing'.
There are plenty of 'online calculators' you can use(try 2-3 to see if they agree ).

Now if you're going uphill, 1PSI will push water up about 2 feet, so 1/2PSi per foot. If you need to go up 50', pump needs 25PSI. If you want 40PSI pressure up there, set pump for 65 PSI (25 for rise, 40 for flow ).

re: 800' run. I'd have run a continuous pipe(no joints) with a fox wire.

Fox wire? Also it has very few joints, the main one being whare it was extended at one point. My dad dosen't remember if he was able to get a roll that long or if it needed a joint. I suspect theres 2 plus the T that sends a line to the switch and pressure tank.

I used a few online calculators but that all seemed to say that on an 800ft length I should only lose 4-5 PSI not 20. Also it's flat so no uphill losses.

I'll have to look up what a fox wire is though

 

[GreensvilleJay]

'fox wire'... It's a solid copper wire( think single wire used in conduit runs...) taped to the pipe, with ends available at terminations. You clip the signal generator ( the fox) to it and ground. The 'receiver( wand aka 'hound' ) you use to FIND the pipe.
Probably a 100 names for the pair of devices. 'locate' guys have real fancy ones can tell depth as well as location. I used to make them 4 decades ago..sigh, time flies.....

 

[ctfjr]

As @GreensvilleJay stated the pressure drop in a line is determined by the resistance of each element of the line (sometimes referred to as 'equivalent length' of pipe). Here is a quick table I stole off the internet:

When you add up all the elements in a line you will have the equivalent length resistance of a straight run of pipe. There are plenty of charts you can then find that will show you the actual pressure drop as a function of the pipe size, equivalent length and flow. The only time the pressure will be the same at both ends is when there is 0 flow - a static condition. As soon as there is flow there will be a pressure drop.

 

[Shadow_storm56]

'fox wire'... It's a solid copper wire( think single wire used in conduit runs...) taped to the pipe, with ends available at terminations. You clip the signal generator ( the fox) to it and ground. The 'receiver( wand aka 'hound' ) you use to FIND the pipe.
Probably a 100 names for the pair of devices. 'locate' guys have real fancy ones can tell depth as well as location. I used to make them 4 decades ago..sigh, time flies.....

Oh basically so it's easy to find the pipe later, well that's smart!

 

[skeets]

Yinz beat me to it,,, we had something like that with the green houses, a bud showed me the chart and we went from 1/2 inch ,I mean it works in the house right,, to 1 inch and removed as many fittings as we could and went in to a manifold a bit of a PIA bit that solved the problem she was having. Now granted the run was only about 300 feet to the green houses but it did make a difference