Well Pump Troubleshooting

[fastline]

Yeah, no pigtail on this one.

With a new controller it does the exact same thing, so it can’t be a bad relay.

It’s not common for these pumps to fail, especially after such a short time, but, if you have eliminated all other possibilities, then whatever remains, however extraordinary, must be the truth.

I have bypassed the OL and got LRA on the pump. I have tested and then switched out the start cap and relay. I have bypassed the float switch. I have ohm’d out, and meggered the pump windings, and the readings are perfectly within manufacturer specs.

Whatever the problem is, bad splice, jammed impeller, corroded shaft, whatever, must be at the bottom of the well, because I’ve tested everything (that I can think of) at the top.

I know your specialty is well pumps, so if you have any other advice I would certainly be receptive.

Additional, I know you are not the plumber here but this is a trick I use for low performing wells to help protect it. I install a gate valve right off the pitless as a throttling valve and and tune that while I monitor the dynamic draw down on the well to ensure there is decent balance there. I had a case about a year ago on a special drip irrigation system but the well (I even confirmed in tests) was only safe at 2GPM. I throttled a personally selected low lift 1/2HP pump just below that and tuned the irrigation drip to run with that, and I ran a very large volume tank with prescribed watering intervals so we would get good recharge.

In those gate valve cases, I remove the handle and ziptie it and a tag to the pipe so people don't jack with it.

 

[fastline]

There are some centrifugal that have a "Hooked Performance Curve" meaning that maximum PSI occurs at something above zero flow. I am told that when in the right application they can be very efficient. The problem is when there are multiple pumps connected to a common discharge manifold. Being that they start at zero flow, they aren't making enough pressure to overcome the pressure in the manifold.

Keep in mind that this is a pretty rare occurrence at least in my experience. Lots of engineers just stay away from pumps with a "hooked curve" in any kind of parallel operation.

But yeah, for the most part you are right

There are lots of advanced setups, especially in high performance applications. In something like you are mentioning, we sometimes do a recirculation circuit to get water moving. Others might be a 2 stage with surface mount intensifier. Watering golf greens at 120psi. What becomes paramount is air intrusion. I assure you, a little air can eject the guts of a 2 gun Rainbird about 100ft in the air.

 

[kwired]

Most starters are built mostly the same thus why I indicated the test at the well head where there is usually a pigtail. But, if you have condemned the pump, is what it is. Hopefully you find the culprit. Report back. Pretty rare that that a pump is stuck unless sand logged.

I've had them stuck because of failed bearing before. Or at least sticking enough to cause pretty high loading.

 

[kwired]

Scenario: 1 phase 230V well pump, separate pressure pump in system, so well pump only pumps to storage tanks.

HO called me because they feel the well pump hasn’t been coming on much. It is very typical for this well to run dry anywhere from mid summer to late fall.

System is as follows: 20A 2P breaker - low water/overload control box - box with contactor for float switch - motor starter with start capacitor.

As far as my opinion, it’s working as it should. Controller is showing OL when float switch calls for water.

What I did: Jumpered float switch; controller shows OL.

Bypassed low water shut down, jumpered float switch, nothing comes out of pump, but clamp meter shows 31-32 amps going to well pump, load side of motor start controller.

Tested capacitor, tested good.

Pulled motor leads from controller. Tested Ohms. Got 15-16 ohms on run windings. Manual says 3.5-5.6.

Meggered motor leads. Got 220M ohms on both leads.

Two areas of concern for me: In the interest of being thorough, I don’t have any way to absolutely verify that the pump is going into OL because of no water, or because of a possible problem with the impeller, clogged screens, etc., without pulling the pump. Unless there is something else I can do.

And 2, what would be the cause of having a slightly higher Ohm reading? I know what an infinity would mean, but what about when it’s just a little higher than it should be?

Pump was replaced about 6 years ago, so shouldn’t be worn out ideally.

Sounds like after reading other posts you probably have bad pump or motor, but the answer to this question is the chart you later posted is the resistance of the windings, if testing while it is down in the well casing you also have resistance in the length of conductor between where you are measuring and the motor itself. Their publications I believe do have other tables telling you what it should be with certain size and length of conductors in the measurement.