Polaris booster pump overload

[Sunfire]

20x40 IG vinyl pool approx 20 yrs old. Purchased w/Polaris 380 that has a booster pump (motor Century 1081/AO Smith B625 - 3/4 hp 3450 rpm 230v). The booster pump is original.

The Polaris has not been run in 5+ years as the port on the pool wall was mangled. Had the liner replaced and port fixed.

When I run the booster pump it will run for a good 15 minutes and then will go off. I believe it is tripping on thermal overload (motor casing is HOT!). I tried running it without the Polaris connected (no/low load) and it still happens.

There is a little bit of air getting into the system as I can see some bubbles exiting the port, it I don’t believe enough to impact the pump operation.

The pool piping is 1-1/2 and the suction is at the bottom of the line between the filter and the chlorinator - all original. New fittings were installed on both the suction side and discharge side where the pump line connects to the pool piping.

I can spend the rest of the summer chasing the small system leaks, it again, I don’t think that’s it. They are present in the pool return as well and it’s been running for a month with no issues.

Any suggestions on what I should be looking for? I thought I’d pull the pump head apart to see if there’s anything obvious broken, but it seems to run okay for the first 15 minutes, indicating it can move water.

Suggestions on where to start greatly appreciated.

[Sunfire]

Just to close this out…. Removed the cover where the electrical service is wired to the motor, and found some of the wired insulation worn away on the black wired which was almost touching the green stake-on. Adjusted the wire positions to create some space between the two and wrapped the wires with electrical tape.

Purchased a new start capacitor from Amazon for less than $6 and installed.

So far the booster pump and Polaris seems to be working.

I ordered a new pump motor just in case. It will either be returned or placed on the shelf.

[Denniswiseman]

That's great and good that you posted back as a help to others