Right Sized Pressure Tank?

[KennyG]

Hello,

Here are some stats on my new system.

Pump = Goulds 3/4hp 10GPM
Drop pipe and water line = 1.25"
Well = Can produce 12 GPM non-stop, well is 67 feet deep with 45' of water. Draw down on the well is 5 feet at 12 gpm flow.

I'm looking to use a 50/70 pressure switch.

I bought a 52 Gal Pressure tank, will this suffice or do I need to go 82 gallon?

My house is a 3 bedroom 2 bath.

Thank you.

 

[Reach4]

52 should be fine.

You probably would have been better with a 1/2 HP pump instead.

 

[Sponsor]

 

[KennyG]

52 should be fine.

You probably would have been better with a 1/2 HP pump instead.

Thanks!

The well is around 240 feet away downhill with around 40 feet drop in elevation. Just wanted to make sure I get the max pressure and flow available due to my fire sprinkler. I also might irrigated my landscaping.

 

[Reach4]

If irrigating, it is best to either use all that the pump can produce, or to add a CSV before the pressure tank. In that case the tank could be smaller. Worst case is that your irrigation uses half of what the pump can pump.

 

[Valveman]

Water comes from the pump and well, not the pressure tank. The pressure tanks only purpose is to limit the number of on/off cycles, which is what destroys pumps and everything else in the water system. Yo cannot get or install a large enough tank to eliminate the on/off cycling. As Reach said, you can either make EVERY sprinkler zone exactly 10 GPM, or use a Cycle Stop Valve. The CSV will allow you to use any amount of water down to 1 GPM without cycling the pump. The CSV will maintain a strong constant pressure of 65 PSI, instead of the pump cycling on and off between 50 and 70 over and over and over. Then when you have a CSV to eliminate the cycling, not much of a pressure tank is needed. The CSV makes the pump produce exactly the same amount of water that is being used, so there is no water left to enter the tank. Water goes right past the tank and the system doesn't know if the tank is 1 gallon size or a million gallons.

Although the CSV will work fine with a 50 or 80 gallon size tank, the larger tanks are a waste of money and space and actually make you wait longer to see the strong constant pressure from the CSV. With that size pump and a 50/70 switch I would have used a 10 gallon size pressure tank with the CSV as comes in the PK1A kit like this.

PK1A Pside-Kick Pressure Tank Kit – Cycle Stop Valves, Inc

Buy It! Interactive Animation Installation Video General Information Typical Applications Specifications Dimensions Installation Instructions Troubleshooting VFD Controller Replacement WARNING: This product can expose you to chemicals including nickel, which is known to the State of California...

cyclestopvalves.com

But since you already have a pressure tank, switch, etc, all you need is the CSV1A valve that also comes with the kit.

Like this.

CSV1A CYCLE STOP VALVE

Compare to the Competition Model CSV1A CYCLE STOP VALVE is recommended for 1 to 25 gpm and is adjustable from 15 psi to 150 psi. It is a stainless steel valve with a molded thermoplastic spring cage. It also has three additional ports (2 - 1/2" and 1- 3/4") and can be used as a pressure tank...

cyclestopvalves.com

A 50 gallon pressure tank only holds 15 gallons of water and an 80 gallon tank holds 20 gallons of water. Unless you want the pump to cycle on/off for every 15-20 gallons of water used, you need a Cycle Stop Valve.

 

[Taylorjm]

I went with an 84 gallon pressure tank. Up from the stock 20 gallon that was in there. Made a huge difference in the amount of times the pump goes on and off, but then my tank fills up at 17 gpm.