I will end up with 2 water tanks on 2 opposite sides of my 10 acre farm. I will also end up with booster pumps on opposite sides. Each booser pump is fed from its own tank.
Is anything bad going to happen with my system if I have both booster pumps supplying all of the pressurized water lines at the same time? To me it sounds like I am better off doing it this way - basically ending up with a fully redundant system.
If you don't think it's a good idea, I am able to dedicate separate lines for each pump.
The pumps are 1500 feet from each other. And the mainline feeds off those pumps run another 800 feet in the other direction from one of the pumps.
Do you think that an open spigot 2000 feet away from a booster pump will activate that one instead of the one closer to it - assuming that the 'turn-on pressure level' are set close to each other?
So I will have both of the pumps set to activate at 45 psi, and turn off at 60 psi. A spigot is open. That spigot is 400 feet away from one pump and 1900 feet away from the other pump. My guess would be that the pump closest to that spigot will go off first.
Maybe I'm wrong, and maybe it is just better to have one booster pump for separate parts of the pressurized water delivery system.
It should work just fine. you may find that one will tend to come on before the other. The water sytem I was on in Olympia had 6 boost pumps all in parallel. Sometimes all six ran and somtimes one or none ran. They all drew from a single 20,000 gal tank and each fed a seperate pressure tank. Most municipal sytems have mulitple boost pumps. Actually I think you will find you have more consistant pressure with that system thn trying to put one big one at one end or the other.
This sounds like a it's filled with potential problems. To pump water 800 to 2000' and have the volume and pressure you want is a sizeable task. To get two pumps on two different sources of water to work together should be a bit difficult IF you don't want most of the water coming more from one source than the other. Just the pressure loss in all that distance and the type of material you choose for the lines is substantial. I suggest 1000' rolls of 200 psi rated PE (polyethylene) tubing. Due to the length, they probably will be special order from most pump supply houses but they are available and it is the best choice.
The pressure you mention is way low if the switches are at the pumps. If you want 50 psi at the tap, the pressure at the pump is going to be a lot higher due to friction loss in the pipe to the fixture. With two pumps, you need to prevent them from working against each other when both are running. You'd need a check valve in each line to do that. Each check valve will probably have a 5 psi cracking pressure. That needs to be calculated into the total 'head' of the system, or said another way, the pressure loss from the pumps to the higest elevation of the fixtures. If this distance rises from the pumps, that takes more pressure at the pumps etc.. If if the topography is flat or downhill, there is nothing but the friction loss of the tubing, but uphill you lose x psi pre foot of elevation.
[img]/forums/images/icons/tongue.gif[/img] Actually, SLO, the only problem you have is this: When the system pressure drops as water is used, the pump closest to the usage will feel the drop in pressure and respond. Sometimes in systems with long lengths of small diameter pipe, the pump builds so much pressure when it starts that it can actually kick off the pressure switch and then the pressure drops and the switch kicks the pump back on and then the pump pressure kicks the switch back off, and then.......well, you get the idea. That scenario can go on and on. What we have done is install a smaller bladder tank with a pressure switch connected to it alongside the normal tank. The bladder tank and the pressure switch are fed through a very small orifice so that the changes in pressure in the tank and therefore in the sensing area of the switch are dampened so that it gives the water in that long pipeline time to get moving, thereby reducing the effect of that surge that occurs from pump start-up. You'll need a similar setup for each pump. Set the pressure switches so that one pump kicks on and as the pressure continues to drop, the second pump kicks on. Those set points will have to be dinked with a little to compensate for the line losses, but it is easy to do that. [img]/forums/images/icons/tongue.gif[/img]
Actually SLO, as you open any tap the whole system is going to see the pressure fall. And buried line isn't going to expand or contract based on that perssure drop. At least it doesn't in wells with 600' of PE tubing drop pipe and a couple hp pump on the far end with a check valve in it. And that line can expand because it's hung in air and then water. I've worked on a fair number of wells, and some of them are 400-500' deep and 200-300' from the house/building and they haven't had any surge on/off problems. For general disscussion purposes, water in a pipe acts like a steel rod, push with a pump and it basically all moves as one piece. There can't be more pressure in one place along the line than another. Now an improper differential setting in the switch and/or no check valves in the lines from each pump would allow that due to the pumps having to work against each other at start up. Hence dinking with the switches, but then IMO, that should be to get both pumps started at the same time.
You might want to look into Cycle Stop Valves on each pump, that would be a better solution. www.cyclestopvalves.com
[img]/forums/images/icons/tongue.gif[/img] Uniform pressure thoroughout ANY piping system is only possible if the velocity is ZERO. Under any other flow conditions, there will be variations in pressure; between user and first storage tank; between first storage tank and second storage tank; etc., etc. It's just like one of those "Balancing Reservoirs" excercises from Venard's: "Fluid Mechanics and Hydraulics" [img]/forums/images/icons/tongue.gif[/img]
I'm not so sure about this 'constant pressure all through the system'.
When I open a spigot that is 10 feet away from my booster pump, the pump activates almost immediately. When I turn on a spigot that is 400 feet away from my booster pump, it turns on later.
Well, this is all theoretical although pretty interesting. As I mentioned earlier, I do have both of the systems completely isolated by valves. So I will be able to report on performance after the system is fully connected.
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