Pump Motor running hot and hesitates when starting

[gottliebo]

This forum has benefited me greatly and I appreciate all of the expert advise that one can find here. Here's my first post! I have a 9 year old 18 x 36 in ground, vinyl, 22,000 gallon pool. This year my 3/4 hp Sta-Rite Max-E-Glas PE5D181L Pump has started to hum for about 3 or 4 seconds when I turn it on before it kicks in. I also notice that the body of the pump motor is very hot. I will check air flow for the heat problem but doubt that this would be related to the hesitation/hum when I start it. Is it time for a new motor? If so, any recommendations? I usually run my pump during the day and turn it off at night. The pool is closed each year during the fall and winter here in Wisconsin so we really only use it for about 5 months. Thanks for any help!

Tom O.
Middleton, Wisconsin

[aylad]

Hi Tom,

I'm not the pump expert around here, hopefully one of them will be by shortly to answer your post. I will say that my pool is also 18 x 36, and I replaced my motor at 7 years old (my pool is open year round, pump runtime 10-12 hours/day April through October, 3-4 hours/day the rest of the year, overnight during freezing temps, which are rare) with a 1 HP A.O. Smith motor, and it does an excellent job.

Welcome to the forum!!

Janet

[Poconos]

Hi Tom and welcome to the forum. You're probably right in that the heat isn't related to the hesitation on start. Have some questions:
-- When it does start does it sound normal and come up to full speed?
-- Does it hesitate to start every time?
-- On a cold start how long does it take to get to what you call hot? Remember it is normal for the case to hit 140 degrees or so.

Ventilation is easy to check as it seems you know. If you had a shorted winding you would probably smell smoke. The hesitation is pointing to dirty starter centrifugal switch contacts, or a connection that loosened, or an intermittant starter capacitor but this is unlikely. Let's see the answers to my questions before we go further.
Al

[gottliebo]

Hi Al:

1. When it starts, yes it sounds normal, except sometimes (progressively more frequent it seems) it hums for a few seconds before it kicks in. Sometimes as long as 5 seconds.

2. No. it doesn't hesitate every time. I'm kind of afraid to turn it off now for fear that it won't kick in at all.

3. I will turn it off tonight and let it cool dow and try to determine how long it takes to heat up to what I perceive to be the "hot" temperature. 140 degrees seems fairly hot but I think it is hotter than that. I can touch it and hold my hand there for only about 2 or 3 seconds.

4. No smell of smoke. Everything (sound, flow, pressure) seems normal but for the starting delay and the heat.

I really appreciate the help. Thank you.

Tom

[PoolDoc]

Pump has started to hum for about 3 or 4 seconds when I turn it on before it kicks in. I also notice that the body of the pump motor is very hot.

The pump may not be any hotter than usual -- you may not have checked before.

But, the hesitation on start often indicates some mechanical aspect of motor and impeller is not turning freely. There can be a couple of causes, but in my experience by far the most common cause is worn bearings.

A weak start winding or start capacitor (may not have either -- don't know what motor you have) could also cause a slow start, but usually it would be slowly, the same way every time.

Motors can be rebuilt, but replacing the motor is a 'cleaner' fix if you can do it. Also you may not have a rebuilder in your area. If you get a new motor, be sure to also get a new seal and any new gaskets / bushings / washer that are long the path of the motor shaft.

PoolDoc

[gottliebo]

It's an A.O. Smith motor (Sta Rite Pump - see above) and yes it has a starting capacitor. I assume those can be tested somehow. There's a danger with capacitors I believe because they hold a charge and need to be shorted with insulated screwdriver before being touched, right?

If it is the motor and not the capacitor, should I just look for an identical replacement or are there more efficient and reliable bands that you would recommend? Or, is nine years not all that unusual for a motor to begin to fail?

Thanks!

Tom

[PoolDoc]

A 9 year old motor? Yeah, that's getting to the outer end of the life expectancy for fractional motors like that. I probably wouldn't rebuild it.

Like I said before, if it was the start capacitor, you'd see the same failure every time, so that's not it . . . or at least, that's not the ONLY problem.

I'm sure there are quality differences between motors, but I wouldn't know how to evaluate them. And the motors are redesigned so often, the 'best' motor could change from year to year.

If your pump is on a lot, I would look for a high efficiency motor. You can compare apples to apples -- if you are comfortable with the tech level -- by matching RLA (Run Load Amps) at equal voltages for given motors. But to do so you must match S.F. (Service Factor) values. High efficiency motors will show lower RLA values at a given voltage, HP, and SF. If this is all goobledy-gook to you, you'll need to match motor to model and simply pick the Hi-E motor if it's a reasonable price difference.

Good luck,

Ben

[Poconos]

Hi again Tom,
Ben has a point about checking the temp. Many people never think to put their hand on it unless they suspect a problem, then it feels really hot when it could be simply normal for that motor and load. The fact it doesn't hesitate every time kind of confirms my suspicion about the starter switch contacts. A motor on my bandsaw went through that phase of having to smack it to get it going 'sometimes'. Finally got to cleaning the contacts and fine ever since. Usually those contacts are behind a cover that allows access to the wiring terminal board. Try cleaning them with 600 grit paper. Auto stores, Home depot etc. If you can get a thin, flat file in there all the better. dress the contacts lightly as they are usually silver and soft. While you're in there check for any loose wiring contacts too. Hope your problem is this simple.
Al