We've got a ADP unit htr. (FOAN200) that wasn't heating. Blw. mtr. was shot. Replaced it and the next day the new one over heated, opening internal limit on the motor. Replaced it again w/ the same results. This motor is direct drive, sealed, 1/8 HP, PSC, 2.7amps. running at 2.8amps @ 120volts, 60Hz. Readings @ mtr. leads while running. Ambient temp. is 75*. Checked cap., propeller pitch, dia. and rotation. Actual temp. of mtr. surf. is around 210* The unit is on its fourth mtr. within a 1 1/2 yr. Any suggestions would be appreciated.