What causes pump to overheat?

[heavynleigh]

We bought our pump 5/29 and installed it a few days later. We replaced a 1 hp pump with another 1hp. It now keeps tripping the thermal cutoff and won't run for more than a couple of seconds. Repairs will cost more than the pump did . Did we just get a bum motor or do I need to upgrade to a 1.5hp?


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[Melt In The Sun]

First things to check are:
voltage - new motor wired correctly for 230v?
motor size - not just HP, but HP x SF (service factor). if your new motor is smaller than the old one, you may need a new impeller.

 

[bobodaclown]

What causes pump to overheat? Excess heat than cannot be dissipated. Sorry. Melt in the sun pretty much hit the key points.

Trouble shooting procedures from motor university:

MOTOR STARTS BUT SHUTS DOWN (Thermal Overload Protection)
1 . Check the voltage at motor terminal. If the voltage is too high, call power company.
2 . Check amperage. If high, find out it the pump impeller was recently replaced (it could be sized incorrectly). Remember, motor Hp x SF = the maximum Hp capability of motor. This number must be equal to or greater than the pump rating.


MOTOR HOT, SMOKING OR CYCLING
1 . Check the motor’s ventilation by looking for clogged air vents or openings. Clean out all leaves, dirt and other pool and spa gunk.
2 . Compare connections and wiring to diagrams. Test the motor voltage to verify that it’s within ±10% of nameplate listing.
3 . If the voltage checks out but amps are higher than the maximum on the nameplate, inspect motor and pump for mechanical obstructions, but not before
TURNING OFF THE POWER.
4 . Ensure that the motor’s horsepower (Hp), times the service factor (SF), is equal to or greater than the pump rating (Hp x SF to Pump Rating). A full-load current greater than the nameplate listing can mean excessive pump load.
5 . Look at motor windings for damage or signs of shorting. Measure winding resistance.
6 . Check the start switch for broken contact welds or a broken spring.
7 . Check the capacitor with an ohmmeter. A bulged capacitor indicates failure on most motors. But with a Centurion, the only way to verify a failed capacitor is with the ohmmeter.

http://www.centuryelectricmotor.com/Motor-Doctor.aspx

 

[mrcarcrazy]

Is there a magic temp (of the outer housing) that should concern you? Or is the thermal breaker the point where you start getting concerned?

 

[heavynleigh]

The pump is on a side of the house where it doesn't see sun. It's shaded by trees when the sun is on that side. Additionally, we only run it at night. It's programmed to go from 10pm to 6 am.

I will have to swing by Lowe's to pick up something to measure the voltage and amperage.

Nothing has been replaced on it. We bought it new on 5/29. It was nice and quiet for the first 6 weeks and has been loud the past couple of weeks. I cleaned the filter and two days later the pump stopped working.


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[n240sxguy]

If the motor itself is making the noise, it could have a bad bearing that is causing it to pull too much current. If you're in the market for a meter, and money isn't an object, get one with a clamp on amp meter. If money is an object, harbor freight has a cheap one that isn't supposed to be all that bad. I plan on getting one the next time I'm in town. You can clamp that around one of the motor lead wires to see how much current it is pulling.

 

[ping]

Possibly a bad seal and now the bearings are shot?