Yes, you could hear the motor hum, but not start.
Second thing I would check is bearings. Does the shaft turn easily? If it's binding, that could also cause it to overheat. A 28 year old pump, my first guess would be bearings.
If anyone on the forum has experience.
I just replaced a 28-year-old Grundfos UP26-99F 230V A/C water cooled pump that runs the ground loop in one of our geothermal systems and it's running fine now. I'll skip the whole troubleshooting experience and just ask my question.
The broken pump symptom was that the motor case got really hot, and the impeller wasn't turning. I pulled the external motor 'casing' off to reveal the internal 'cartridge' and its shaft that drives the impeller, and it wasn't mechanically jammed. That pump has a startup capacitor. If the startup capacitor was bad, would that cause the motor to overheat and not turn?
I don't have that much A/C motor experience. I previously replaced the startup capacitor for one of the compressors in our (previously replaced) geothermal heat pumps, but the only symptom there was the compressor simply wouldn't start. So, my thought was if the startup capacitor failed, this motor simply wouldn't turn. The fact that it got very hot very quickly made me conclude something in the motor internals had failed.
I shall attend any voice of experience that chimes in.
Spoke to someone at the police station today, they were very nice. She confirmed they got my payment and said im looking at another 2 weeks for the permits to be approved. (hoping thats true) Guess we will see.