The blower is an Air Supply Silencer blower, 1.5 HP, 240 volts, 4 amps. It has an Amatek / Lamb motor in it (which pretty much all in-ground spa blowers have the Amatek/Lamb motor, the different manufacturers just wrap different pastic housings around it and stick different nameplates on it). The motor is what is tripping, not the breaker. The wires are #8 copper wire, on a 30 amp dedicated breaker, so that should be fine.

I think I fixed it. The blower originally sat directly on top of the check valve. What I did was add a PVC connector and short piece of PVC pipe (a couple inches). Then drilled a hole (about 3/8 inch) in the newly added short air pipe between the check valve and blower. I just ran the blower for about 40 minutes, and it ran fine. The hole in the pipe exhausts air into the equipment area. This then seems to have reduced the backpressure on the blower, and also allows the blower to move enough cool air over the motor to keep it cool and not overheat and cut off.

I also think I like it better now. Before the bubbles where very large and aggressive in the spa, almost uncomfortable. Now with relief hole that vents off some of the air, the bubbles are smaller and less aggressive. Maybe the blower was oversized to begin with, maybe a 1.5 HP blower is overkill for this installation, maybe a 1 HP would have worked better.