Can timer damage pump with bad capacitor?

Nov 20, 2017
22
Newcastle, Oklahoma
I'm thinking about putting my pump on an Intermatic T101R timer. My concern is what happens if the timer turns the pump on, but the pump isn't able to start due to a bad capacitor?

For the past few years, my pump capacitor will go out at some point during the season. When this happens, the pump will simply buzz when turned on. I have to spin the shaft with a screwdriver to get it going. Since I'm turning it on manually, it's not a big deal as I immediately notice it, but what would happen if the timer turns it on, the capacitor is bad and I don't check it for several hours? Will it sit there and buzz for hours and damage the pump? Should it flip the breaker?
 

mas985

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Usually it will either trip the breaker or the internal thermal limiter switch.
 
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setsailsoon

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That's very unusual the cap would fail every year. I'd look into why that's happening and address that. I'm not sure why that is happening. Could be failing bearings that increase the starting loads or windings going bad or replacement cap is not the correct one or something like that I bet one of our motor experts like @JamesW or @ajw22 would be able to give you some items to check into.

Chris
 

mas985

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Heat and voltage spikes are the usual culprits for capacitor failures. A surge protector might help.

Could also be low quality capacitors being used as replacements.
 
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JamesW

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Mar 2, 2011
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What exact pump do you have?

Is it a start capacitor or a run capacitor?

If it’s a run capacitor, you can use a 440 volt rated capacitor instead of a 370 volt rated capacitor and that will help.

There are millions of timers on regular single speed pumps.

You might have a voltage problem.

Check the voltage, current and power factor on the pump during operation.

Is the pump getting excessively hot?

What is the motor shell temperature?

If it’s a start capacitor, it might be staying in the circuit too long.

Make sure that a run capacitor says “10000 AFC Protected”.
 
Nov 20, 2017
22
Newcastle, Oklahoma
Attached is a pic of my pump. It's a Waterway SD-20-2N11MD. The capacitor I use is the "TEMCo 50 uf/MFD 370 VAC Volts Round Run Capacitor 50/60 Hz AC Electric" from Amazon. I purchased one on May 15, 2018 and then bought another one to replace it on July 22, 2019.

I'll have to check the pump and shell temp during the season when I hook everything back up. It does get really hot, but it also sits in direct sunlight with no pump cover.

I'm guessing the pump was a few years old when I purchased the house and was kept outside year round uncovered. It already had the rust on it in late 2017.

Should I switch to a 440 volt, 10000 AFC protected capacitor and give it a go?
 

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JamesW

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Mar 2, 2011
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Should I switch to a 440 volt, 10000 AFC protected capacitor and give it a go?
440 is a better capacitor. It should last longer. If the motor is getting too hot, that will shorten the life of all components.

There are millions of pumps on timers. So, that should not be a problem.

Try to figure out why the pump is getting hot.

Check the amps, volts and power factor. Check the actual temperature.
 
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