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I have an old carrier Weathermaker DX 58DXA060-100GG, and the blower motor has no oilers. I assume it was a replacement for the original. My question is, because I woke up to it humming and then it started but never shut off until the hi-limit switch was reset, can I put in a different motor? This is a 4 speed motor that is in it. However only 2 speeds are actually hooked up. Could a 2 or 3 speed be used instead? Also, it is a 1/3hp fla5.8 psc, can I use a 1/3hp fla6.1 or fla6.2, or even a 1/2hp fla6.1 or fla6.2? I don't want to spend the $250 for the exact replacement because I would be better off buying a new furnace. This furnace is about 25 years old from my diagnoses and investigation. I have replaced the spark control, the pilot and the inducer motor in the last 3 years. But if I keep replacing parts like this then it might just warranty a complete replacement. I have removed the motor and repacked the bearings with new grease, but it still has a slight moan on start up, but runs for now. I know it will quit again in the future.

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I would replace the motor with a 4 speed PSC motor. Psc motors have more starting torque than non PSC motors and use less electricity to run and start, because they are more efficient. These motors are usually 4 speed however a few are 3 speed. you may want to check the capacitor since the motor will not run if the capacitor is bad and capacitors cost a lot less than a motor.

  • More thoughts; with the motor humming and not turning if you could carefully spin the motor/blower wheel and it then comes up to speed and runs ok and in the right direction, then the capacitor is probably bad. Watch your hand so you don't get your hand caught in the blades. Also with the motor off and electric off try to wiggle the motor shaft up and down. If there is play in the motor shaft the bearings are bad and the motor needs replaced. If your not comfortable doing these things call a contractor so you get the problem solved correctly and not waste your money. – d.george Jan 10 '17 at 10:52
  • I know the reason behind a PSC, just wondering if I can substitute a slightly different motor based on cost. I can get a 2 or 3 speed with a higher amp rating for almost half the price of the OEM. I have had caps go bad in other systems, as a matter of fact, my AC unit bulged the cap 2 years ago during the hottest part of the summer. This cap I was considering replacing just to see. It does start up with a groan, but once fully up and blowing (less than 3 seconds) it sounds fine. spins by hand good, not a lot of shaft play either. I suppose I could try the cap first and post back. – Jeff Cates Jan 10 '17 at 22:15
  • The blower wheel had a stamped manufacturing date of 1991, so if this motor is original (I doubt it since even the blower housing says to oil the motor every 2-5 years) it is well over 25 years old. The cap looks newer, so it has probably been replaced at some point. – Jeff Cates Jan 10 '17 at 22:15
  • On some of the motors you will see a small metal plug that you need to remove to oil the motor. The plug is right on the metal end of each end of the motor. I have also seen little rubber plugs. Some motors do not have a place to oil, they are factory sealed.If you have a motor that can not be oiled I have gotten a little more life out of the motor by punching small hole in the end of the motor in that " metal cap " looking end with an ice pick and using that hole to oil the motor. The only problem you may have is fitting the new motor into the motor mount bracket and make sure of rotation. – d.george Jan 11 '17 at 14:53
  • No oilers, I had to repack the "sealed" bearings. As far as fitting into the motor mount bracket, it is a belly band setup, as long as the motor is the same diameter I can get it to fit. I would also buy a CCW/CW motor so I can get the proper rotation. Today I swapped the run cap out with a new one I had. I will be testing it over the next few hours/days. – Jeff Cates Jan 11 '17 at 22:50
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To find a different motor that will be the same size shaft and mounting you use the frame information on the nameplate of the motor, for an example: lets say a 145T motor will fit they come in many different configurations, 1hp, 1-1/2hp, 2nd. 2nd speeds normally ~1750 rpm or close and 3600 rpm then there are 2, 3,4 speed models. Last is the voltage all this information is on the name plate. If you only need 2 speeds it may be possible to find one that matches the rpm's you are after but the installer may have selected a 4 speed to get the best 2 speeds for your application.

  • I just reread this and stand by my original post but if the motor is not shutting down its not a motor problem but a controller issue. – Ed Beal Jul 13 '18 at 23:09

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