Technical information:

Well depth: 160 feet.
Current static level: Unknown. Can't see the water; however in the winter and spring, the water level is about 10 feet from top of well.

Pump: Franklin 3/4hp submersible (12 GPM I think), installed approx. 8 years ago.
Model # on control box: 2801074915

Tank: Reliance PMD85 (installed 9-15-07)
Pressure at Schrader valve: 28 PSI
Switch: Square-D 30/50

Actual on pressure: 28 PSI
Actual off pressure: 48 PSI

EDIT: Adjusted switch:
Actual on: 41 psi
Actual off: 60 psi
Tank pre-charge: 38 psi

Two ball (check) valves installed on main line: One at the pump and the other at the tank.


Whew! Now that the tech info is out of the way, my problem:

The pump will kick on as it should at 28 PSI, but it seems like it's overwhelmed and can't keep up with demand when I turn on more than a couple of faucets at a time.
If I run only ONE faucet (say water the lawn) the system will work just fine all night long. But soon as you increase demand.. off it goes.

I was timing it this morning and with NO demand on the system, it takes approx. 5 minutes to fill the tank and about 2 minutes to drain it.
When you have a small demand ON the system (say one faucet), it takes about twice as long to fill. If I have two faucets on, it can't seem to keep up.

Now here's an interesting part:

I disconnected the pipe at the top of the well and turned the pump on.
It ran just fine and pumped water with no problems. I ran it for several minutes this way.

I also did a rough GPM test and in one minute, it filled approx. 2 1/2 5-gallon buckets.

So why can the pump run fine under no pressure, and shut off when it is? Am I looking at a weak pump?

I also did all the electrical tests that I could.
Per Franklin's test procedures, my pump and control box all passed.

EDIT: I just measured the amperage again:

Black wire: 7.9 amps
Yellow wire: 7.9 amps
Red wire: 0 amps

Any ideas?