So, no more speculation. I bench tested my Gast 0523 pump this morning with a fluke amp meter (clamp-on style) and obtained the following results. I simulated different pressures by gradually closing off the air flow and had the pump wired for 115 volts...
Steady-state operations:
0 psi = 3.6 amps
3 psi = 3.9 amps
5 psi = 4.1 amps
6 psi = 4.2 amps
7 psi = 4.4 amps
8 psi = 4.6 amps
9 psi = 4.8 amps
10 psi = 5.0 amps
11 psi = 5.2 amps
12 psi = 5.4 amps
13 psi = 5.7 amps
14 psi = 5.8 amps
15 psi = 6.2 amps
20 psi = 10 amps (this 20 psi point was captured at the point the pump was just about to flutter/sputter and start dogging down.
I checked the start-up inrush at 5, 8, and 10 psi and it measured 23 amps througout the range.
As you can see in the psi/cfm chart that they stop at 10 psi...that is the 5 amp mark you were referring to.
I hope this makes up for my earlier, foot-in-mouth assumptions.
