Water well start capacitor burns s

Factual Questions
1

I have a water well but no idea how long it has been in. When I moved into the house, I looked at the control box. The capacitor looked as if it was melted from the inside. I replaced the entire box but as soon as I turned the power on, the capacitor began leaking fluid and smoke. I replace the control box with the same amps/volts as the one that was on it. Any idea what would cause this? Hoping to not have to remove the pump.

2

Did you check the power lines to/from the pump for fraying?

I had this happen last year and it was a frayed power line, but we didn’t find it until after pulling the pump.

3

I did not see any fraying, but am hoping not to pull the pump.

4

Sounds like a shorted winding in the motor.
Or, the centrifugal switch is broken and not turning off.

5

I’d be a bit concerned about the quality of the control box. Even if the pump is bad a new capacitor shouldn’t fry like that.

You need to do an electrical check. The red yellow and black wires go to the pump. Test each of those to ground with an Ohm meter. I expect each will show a dead short.

Take a picture of the old control box, and the area of the pressure tank. I can probably tell you a bit about the pump.

6

One thing’s for certain, the starting capacitor is pooched and will need to be replaced. It may be cheaper just to buy the whole box again.

I replaced my control box years ago because of a dead capacitor with no issues. Something else is the cause of your concern and you probably need an expert to troubleshoot that.

7

It’s better to just to replace the control box, the issue could also be the relay is bad, which fries the capacitor. It also works vice versa.

We used to carry the components, test, replace and rebuild control boxes as needed. Now with labor rates what they are it’s cheaper for the customer to swap out the box. It’s 2 minutes to swap a control box cover. It’s a half hour to rebuild them.

8

Ha. That’s exactly what I replaced, come to think of it. The electronics are in the cover and all I did was plug the new cover in and tighten the screw.

9

I have a multimeter but not really sure how to use it. I set it on 2000 k ohms and it reads “I” for the yellow wire when placed on the ground wire. But reads “230” for the red and blk.

10

‘1’ means infinite.

You’d need to make sure you are testing the wires that go to the pump. The incoming power can also be red and black. most common with incoming is black and white.

I need pictures.

Ohm readings red to black, red to yellow, yellow to black?

11

You need to call someone. You can’t fix this yourself.

12

Back about a decade ago, a large number of computers were made with faulty capacitors - after a few years of use the capacitors started bulging, then failing. The fluid inside was incorrectly formulated, causing the capacitor to fail.

I have not heard of this being a problem with large electrolytic capacitors for power uses; generally the problem I’ve seen relates to pencil-tip-eraser-sized capacitors on computer motherboards. But it’s possible this is why the capacitor failed, and it’s the source, not the result, of the problems.

13

I do have to admit defeat and agree with you.

Problem is most likely the pump. There is a chance if he/she rewired the control box wrong it created the issue, in which case they should have called a professional to begin with.

14

Could be as cleaning and lubing a centrifugally operated switch…

See Another motor start capacitor craps the bed

15

It’s not difficult to check a three-wire submersible pump using a ohmmeter.

The motor in the pump has two windings: a start winding (red & yellow) and a run winding (black & yellow). The metal case of the pump is connected to the green wire, and we call this “ground.”

After cutting power to the control box, disconnect the four wires (red, black, yellow, and green) from the control box. Measure the insulation resistance (IR) between the windings and ground using a ohmmeter (or better yet, an IR meter such as the ones made by Megger):

  • Measure the resistance between the red and green wires. It should ideally be infinite. A reading above 2 MΩ is generally considered to be “good.”

  • Measure the resistance between the black and green wires. It should ideally be infinite. A reading above 2 MΩ is generally considered to be “good.”

  • Measure the resistance between the yellow and green wires. It should ideally be infinite. A reading above 2 MΩ is generally considered to be “good.”

(Note that if there are no discontinuities in any of the windings, then only one of the three above measurements needs to be taken. But it’s simple to do all three, so you may as well do all three.)

Next measure the resistance of the start and run windings using an ohmmeter. The nominal values for each are found in the installation manual. For most 3-wire pumps, the resistance of the start winding is somewhere between 10 Ω and 20 Ω, and the resistance of the run winding is somewhere between 3 Ω and 6 Ω. The resistance values will also include the resistance of the wiring, so don’t be too hung up on the precise value:

  • Measure the resistance between the red and yellow wires. For most pumps it’s between 10 Ω and 20 Ω. A very low value (e.g. 1 Ω) is indicative of a shorted start winding. A very high value (>1 MΩ) is indicative of an open start winding.

  • Measure the resistance between the black and yellow wires. For most pumps it’s between 3 Ω and 6 Ω. A very low value (e.g. 1 Ω) is indicative of a shorted run winding. A very high value (>1 MΩ) is indicative of an open run winding.

  • Measure the resistance between the red and black wires. (You are measuring both windings in series here.) For most pumps it’s between 13 Ω and 26 Ω.

16

Hah! That explains the graphics card failure from eight years ago–when it died, most of the electrolytic caps looked liked they vomited foam.