I have an Aqua Spa Pak pump unit (circulation pump) on our hot tub that recently had its motor bearings seize on it. The motor is a 1-1/2hp, 2 speed (3450/1750), 230V Emerson motor that has a wet end installed on it by ITT (Marlow).

The motor seized when it was on the low speed setting.

After I replaced the bearings on the motor and turned the pump back on the low speed setting (activated by pressing the air pushbutton) the motor to pulse at approximately 1 sec intervals.

The pump operates normally (no pulsing) on the high speed setting.

I'm thinking that the motor may need to be replaced, but am hoping that there may be a way to salvage it.

Please advise as to why the motor may be pulsing on the low speed setting. Any help would be greatly appreciated.

-H

No expert on this, but did service a few pumps, years back.

Could be a capacitor that is starting to break down inside - capacitance builds up, then arcs?

Try running the pump off a normal socket, or try running another appliance from the air button (a light or whatever) to isolate the air switch from the problem.

Should be a cheap option to try...

Anyone else?