I have a Bell & Gossett series 100 booster pump. The motor/power pack shuts down after 5 seconds of operation, cools down, runs for 5 seconds, etc. The motor makes no abnormal noise, and this happens even when it starts cold. I suspect a failure of whatever mechanism it is that detects and determines that a thermal fault has occurred. I've confirmed that the power reaching the motor is constant, and I've removed it from the pump with the same results. All the manuals for these system offer little to nothing in the way of servicing these power packs beyond oiling and replacement of the motor mounts. The mounts on this unit are in good condition, and it's been oiled. Does anyone know if it's possible to "fix" this problem beyond replacing the entire power pack?