Pump has stopped....what now?

[Defgufman]

Hi all, I have pentair sf-n1-3/4a pump that is 2 years 5 months old. Today I noticed the pressure was 0 and the motor was hot to the touch, but not pumping or even making a sound. My question is would you replace with the same or look for something different? Also can I just change out the motor and is that the best choice? Last, would you go up in HP if it were your pool? Thanks for the help.....

 

[PebblePool]

Hmmm, I have a pentair pump and my capacitor went out after 2 years, replaced the capacitor. Did your breaker trip?

 

[Defgufman]

No it never did. The Polaris was running and it never even stopped.

 

[Defgufman]

Update if it helps- it seems to be a heat issue. If I wait for about an hour it will come on again but only for about 15 minutes before shutting down again. The Polaris keeps running even after the pump stops. Also, the pump stops even if Polaris isn't running.

 

[JamesW]

Check volts and amps while running.

Check capacitor.

Check shaft to see if it spins freely.

 

[kadavis]

Turn off the polaris pump and leave off until you fix the main pump. Otherwise you may be replacing two motors

 

[kadavis]

That is the Pentair Superflo pump. It has a total hp of .93. Seeing that your pool is less than 14000 gal. and you have a sand dollar filter this is probably the right size pump. If you go with a larger motor you will also have to go with a larger impeller to increase the flow. When the pump comes back on is it primed and running at usual pressure?

 

[Defgufman]

Okay, so I did after I read this, and it has run problem free since. It seems to be connected to Polaris after all...

 

[JamesW]

What did you do to fix it?

 

[Defgufman]

I haven't fixed it, just turned off the Polaris and it seems to be working fine. I'm wondering if the Polaris is the issue.

 

[kadavis]

Can you post a picture of the electrical hookup of these two pumps. Are they on the same circuit?

 

[JamesW]

Might be a problem with the voltage. With both pumps on, the voltage might be dropping too much.

If you're comfortable measuring voltage, check voltage with the pumps both off, then with main pump on and then with both pumps on.

You can also check amps of each pump to see if one if pulling too many amps.

 

[Defgufman]

This is strange though that it would be a voltage all of the sudden. Nothing has changed for the last few years. I'll post pictures in a minute. Where I stand now is the pump seems to run fine by itself. I ran it for 5 hours last night without a problem. If I turn on the Polaris it runs for about 15 minutes then the main pump stops, but Polaris keeps going. This is especially odd since usually Polaris won't if the pump is not running.

 

[JamesW]

The Polaris switch gets its power from the load side of the pool pump switch so that it can only run when the pool pump runs.

I suspect that the main pump motor is beginning to fail from bad windings or a bad capacitor. The capacitor can be replaced if necessary.

I also suspect that the wiring connections might be corroded. With corroded connections, the voltage can drop too much and cause the motor to overheat.

When wiring is not under load, the voltage at the pump will be the same as at the panel.

However, when any load is put on the wiring, the voltage will go down some.

How much the voltage drops depends on the total resistance of the wiring and the load in amps.

With only the pool pump on, the voltage is probably high enough to make the pump run.

When you turn on the Polaris pump, you double the load in amps and double the voltage drop.

Low voltage causes the motor to run at higher amps and overheat.

I suspect that the wire connections slowly corroded over time creating more and more resistance.

I would start by checking amps and voltages. Then check wire connections and switches.

Switches eventually fail. As they age, they can create excessive resistance.

 

[Defgufman]

Thanks, I'll trouble shoot that direction.

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[txnole]

I'd look hard at the capacitor on the Pentair side, the sooner the better.

 

[Defgufman]

Thanks I think you are correct

 

[JamesW]

I suspect that there might be at least two issues combining to cause the problem.

Since the pump works with the Polaris off, that points to a voltage issue. I suspect that when both pumps are on, the voltage goes below 220.

I think that there could also be a problem with the pump. It could be a weak capacitor. I don't think that the capacitor has completely failed because the pump still starts.

It might be the windings going bad.

You might find that a new capacitor makes the pump work. It might be that the undervoltage is tolerable with a good capacitor.

I would start with a new capacitor. Then check volts and amps of both pumps while both pumps are on.