3hp submersible

Hi I'm new to this. I have a few acres. There used to be a 7 hp hallow shaft pump about 150'. The shaft broke then the motor took a dump. After many hours of headache and if I should replace the motor. I decided to just pull the shaft and impeller. With me my brother and a friend we pulled out the 2.5" galvanized pipe 150' long with a cherry picker and a couple hoist. Took us about 6 hours but we did it safely.

Now I decided to go with a 3hp 3phase 37gpm@157ft submersible. I wanted to know if I could still use the 2.5" pipe and just reduce to 2" on the pump? The pump is just going to be for watering about 1 acre of grass. And then used to fill up a water truck with a 500 gallon tank every so often and if i get a good flow maybe plant an orchard Some of my main concerns are=

Can I use the 2.5 inch pipe?

Do I need a ptless adapter?

Do I need a pressure tank?

Can I use a pressure tank?

Will it be enough water?

I also have a big tank next to the well opening about 300 gallon it looks like a big ball. I was wondering if I could cut out the top of the tank. so the submersible could feed the tank and I have a 2hp Wayne sprinkler pump Being fed from there to hook up to a sprinkler system. Cause I've heard that the submersible pump cannot be pressurized due to size of hp. Please help. Or tell me exactly what I need to do. Thanks

Yes you can reuse the old pipe and reduce the size at the pump.

What was being used to support the old pipe & pump? A well seal? You can reuse that also and bring the wire through one of the smaller ports in the seal.

No you don't need a pressure tank, but you do need a way to control when the pump goes on & off. You could use a float switch in the big tank wired in to the 3 phase starter to accomplish that.

Submersible pumps absolutely can have back pressure on them.

Double pumping can be expensive and a real pain if you don’t need it. I would get a pump that would produce good water from 265’, so it can lift the 150’ from the well and still produce 50 PSI for the sprinklers. If you are careful to ALWAYS use enough water to keep the pump happy and the pressure from getting high, then you can just turn on the pump manually when you want water. A pressure tank and pressure switch would allow you to just open a faucet when you need water, and the pump will come on and off automatically. With that size pump and variable flows required, you will need a large pressure tank or maybe two or three to limit the pump from cycling on and off. Or you can use a CSV with a small pressure tank and be able to use the water anyway and at any flow rate you want.

Thanks for the help I really appreciate it. I have a control panel also. And it came with a float control. I'm only gonna be using this well every so often.

Don't know why you would need a float control. A 25 GPM, 3 HP pump will deliver 27 GPM from 150' and 50 PSI.

Ok now I have a wireing question. I have a roll of 12 gauge braided wire single strand I have about 1000' could I just cut 4-150' prices and hook that up or do I need to get special 4 wire cord

As long as you get the colors right it will be fine. However, I prefer double jacketed wire as it handles abrasion better.