Storage Tank/Irrigation help needed

[fernf5]

Searching the internet for help because of my lack of knowledge I stumbled upon this site. Seems like the knowledge needed is certainly here.
There is a long backstory here but I'll try to keep this short.

I installed an irrigation system and 500 gal. holding tank that is
fed from my 5 GPM well. The holding tank is enough to water what we need (backyard) but
it only refills when the house holding tank empties during normal use. This
leads to being out of water for 1 1/2 to 2 hours at random times while the 500 gal tank
refills. We have a pump control switch installed to start the pump in the
500 gal tank. I am hoping there is a way to install a float type switch in
the 500 gal tank and have it start the well pumping water when the level
goes down. Then we could irrigate at night and not be without water for long
periods. There is a float valve in the tank which shuts off water when it is
full.
What I need to know is what equipment I need to install be able to control when the well fills the 500 gal. holding tank. I'm a complete rookie at this. That's why I didn't get it right when I initially installed everything and am trying to retro fix it.I've read a lot of posts here but haven't been able to get an exact answer.

I attached a "line" drawing to hopefully make things clearer.

 

[Valveman]

The float switch should be the only control needed for the well pump. Put the pressure tank and pressure switch on the booster pump in the cistern and let it run the irrigation AND the house from the cistern. Like this.

 

[Sponsor]

 

[Valveman]

Or you can use a pressure tank control on both pumps and have the option of running the house directly from the well pump OR from the cistern booster pump. Like this.

 

[fernf5]

Thanks for the reply Cary. As I stated, I'm a rookie at this stuff. Always been a DIY type of guy but I've decided at this stage in life there is more to this than I care to learn. Called a local pump expert to see what his opinion is. I'll probably have more Q's once I speak with him. All I really want to know is how to add the float switch, control it and specifically where and how it is connected to my existing controls. Stay tuned, I'll be back....

 

[Valveman]

This drawing has a wiring diagram for a float switch and Cycle Sensor, which is pretty important with a 4 GPM well.

 

[Ted Daniels]

Or you can use a pressure tank control on both pumps and have the option of running the house directly from the well pump OR from the cistern booster pump. Like this.
View attachment 46661

Looked at your diagram. I have tried the exact same layout except I thought I could cut out the booster pump on the side delivering water to the house from the tank (in my case trailer) as I have about 18-20ft head of water in the tank. Puzzling as I get no flow at all

 

[Ted Daniels]

I tried the exact same layout and as I have a 20ft high tank I thought the head of water would drive enough pressure at the trailer about 150ft away, that I would not need the booster pump so could use the same line I use to fill the tank from the well to deliver water back to the trailer. Did not work so scratching my head

 

[Reach4]

I installed an irrigation system and 500 gal. holding tank that is
fed from my 5 GPM well. The holding tank is enough to water what we need (backyard) but
it only refills when the house holding tank empties during normal use. This
leads to being out of water for 1 1/2 to 2 hours at random times while the 500 gal tank
refills. We have a pump control switch installed to start the pump in the
500 gal tank.

Submersible pump in the well I presume. If you take the superfluous check valve out that is probably near the pressure switch out, or remove its innards, then opening the valve to feed the 500 gallon tank should start the well pump. If you post a photo that includes the pipe from the well, the pressure switch, and the input to the pressure tank, we can point out the check valve. Normally you only want a check valve in and/or at the pump.

 

[Bannerman]

I have about 18-20ft head of water in the tank. Puzzling as I get no flow at all

20' head = ~8.6 psi. Depending on if there is a check valve in the line from the tank, the check valve will likely use a spring to keep the CV closed so there will be pressure needed just to open the CV which will further reduce the pressure downstream. In addition, there will be friction within the 150' piping to the trailer in addition to any fittings such as elbows, joiners etc which will increase the effective length of the line beyond 150'.

 

[Valveman]

Gonna need a pump.

 

[Ted Daniels]

Gonna need a pump.

The problem with another pump is I have to run a generator for electricity as we are miles from nearest electric supply. My initial hope was I could run the generator and fill the storage tank, then just let gravity do the distribution, either to trailer or irrigation lines, then just top up the main tank periodically. Maybe have to install solar panels to power a secondary pressure pump. What are your thoughts on that?

 

[Reach4]

The problem with another pump is I have to run a generator for electricity as we are miles from nearest electric supply. My initial hope was I could run the generator and fill the storage tank, then just let gravity do the distribution, either to trailer or irrigation lines, then just top up the main tank periodically. Maybe have to install solar panels to power a secondary pressure pump. What are your thoughts on that?

Consider using a laser level in the dark. A friend may be able to loan you one. Or sight across a conventional level. The truck may be at a higher earth altitude.

Also, if you want to empty the big tank, its the altitude at the bottom of the tank that matters.

I presume the output from the big tank is at the bottom.

 

[Valveman]

You can either put the tank on a 100' tall legs do you get 40 PSI or add a pump of some kind. If you don't use much water one of those 12V RV type pump will work and run off a battery. If you need more water than that you will need more power.

 

[Ted Daniels]

Consider using a laser level in the dark. A friend may be able to loan you one. Or sight across a conventional level. The truck may be at a higher earth altitude.

Also, if you want to empty the big tank, its the altitude at the bottom of the tank that matters.

I presume the output from the big tank is at the bottom.

Yes output from the bottom. That would explain everything as I, hydraulically unaware, assumed it was the height of the water level in the tank that mattered if it was a closed system. I assumed the water level would try to equalize out, albeit maybe slowly, through the pipes and over to the trailer.

 

[Ted Daniels]

You can either put the tank on a 100' tall legs do you get 40 PSI or add a pump of some kind. If you don't use much water one of those 12V RV type pump will work and run off a battery. If you need more water than that you will need more power.

I'll have to get my solar panels hooked up and put a decent pump in per yr diagram. They can then deliver electricity on demand thru the inverter. Working this totally off the electric grid is challenging.

 

[Reach4]

Yes output from the bottom. That would explain everything as I, hydraulically unaware, assumed it was the height of the water level in the tank that mattered if it was a closed system.

It is the water level in the tank in an open system. So if the water surface in the big tank is higher than the lower of (the output of the pipe) and (the water surface in the truck tank) and (the highest altitude of the tubing in the path) , and the path is open, water should flow toward the truck.

Sorry, but I wanted to make sure that the pipe was not coming up over the rim and back down.