AC Motor Overheating Question

[Shophound]

Going by the OP, this sounds like a fan coil unit, running chilled water from a centralized chiller. If the apartment is not on a top floor or has a lot of glass/wall area exposed to the sun, it should stay pretty darn cool in there with a chilled water fan coil set on 68.

Motor going out on overload...replacement motor possibly wired incorrectly, incorrect voltage, or run capacitor bad (brought over from original motor, maybe, or new one bad out of box).

The on-site guy handed you a load. Those motors in those fan coils can run and run without overheating if they're wired and sized correctly.

Weak airflow when the blower manages to run is why you're not getting your apartment down to 68. I'd put money on the cooling coil being plugged with drywall dust, as others have said. The original motor windings may have been plugged with dust as well, which is why it failed.

Running the unit without a filter in it is just asking for trouble.

[hvaclover]

I also completely agree with this. Blowers that the HVAC industry uses, whether axial or radial, draw less HP when they do not deliver airflow. If you block the airflow in a canister vac, the motor speeds up. There are some blowers that will increase HP, but they are specialty industrial apps for high head or vacuum.

It is either a bad design on the part of the mfg, or a bad (batch) of motors, or low voltage, or a bad cap or some combination of these. Also as was said, any HVAC motor is certainly rated for 100% duty cycle.

paul

This would be an air over blower. And it would over heat if a dierty filter were in place. But since OP said it was removed then that leaves a plugged coil which is the most likely circumstance since he has only been in th apt for ten days.

The motor speeding up in a canister vac by blocking air flow also causes motor over heating.