Well Pump Troubleshooting

[Seven-Delta-FortyOne]

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.

 

[hillbilly1]

May be a bad splice at the pump. Also start capacitor and/or relay may be bad if it’s a three wire pump.

 

[hillbilly1]

May be a bad splice at the pump. Also start capacitor and/or relay may be bad if it’s a three wire pump.

Just noticed, you did check the start capacitor, may be the relay then. Any current on the start winding?

 

[ptonsparky]

Off hand, 3 times is not a slight difference in ohm reading.

 

[ptonsparky]

Two wires to the pump or three?

 

[Seven-Delta-FortyOne]

Just noticed, you did check the start capacitor, may be the relay then. Any current on the start winding?

Didn’t check that thanks. I’m not a motor expert by any means, would a faulty relay, that didn’t allow the start cap to engage with the start winding, cause an overload controller to go into overload?

My experience with blown capacitors is the motor just sits there and hums and doesn’t start. I know after a while it could burn up the motor.

 

[Seven-Delta-FortyOne]

Two wires to the pump or three?

3. 4 actually. Hot-hot-ground-capacitor.

 

[Seven-Delta-FortyOne]

Off hand, 3 times is not a slight difference in ohm reading.

Is that common to see elevated ohm readings that are far below infinity on a motor?

I would assume the culprit is usually bad splices, or corrosion in a splice.

If there had been water infiltration into the motor itself causing corrosion, or if sediment got inside, I would imagine I would see that reflected in the megger readings?

 

[ptonsparky]

3. 4 actually. Hot-hot-ground-capacitor.

Ok, I was ignoring the EG.

 

[fastline]

Since you said you checked a capacitor, that is a 3 wire pump. Your winding reading sounds like the start winding, not the main. Check BOTH.

If a pump runs out of water, damage is likely. Motor can burn up, but more importantly the impellers and bearings are run dry and damaged. Many times this doesn't fully take out the pump end, but reduces it's performance. Make sure it still achieves good pressure.

 

[ptonsparky]

Try downloading the Franklin AIM Manual.

 

[fastline]

Just reread the first post. You're amperage is a no-go. That is locked rotor amps. Do not leave it in that condition. It's not running. That indicates an issue with the start circuit. Either something at the pump, or the start controller. If you already checked the cap, next is the potential relay.

 

[Seven-Delta-FortyOne]

Just reread the first post. You're amperage is a no-go. That is locked rotor amps. Do not leave it in that condition. It's not running. That indicates an issue with the start circuit. Either something at the pump, or the start controller. If you already checked the cap, next is the potential relay.

I did not leave it like that. That is the reading I got when I bypassed the low water shutoff. That is the reading I should get, if there was no water in the well and no low water shutdown, correct?

 

[Seven-Delta-FortyOne]

Since you said you checked a capacitor, that is a 3 wire pump. Your winding reading sounds like the start winding, not the main. Check BOTH.

If a pump runs out of water, damage is likely. Motor can burn up, but more importantly the impellers and bearings are run dry and damaged. Many times this doesn't fully take out the pump end, but reduces it's performance. Make sure it still achieves good pressure.

This pump has always had a low water shutoff installed . It was only bypassed to troubleshoot if it was working.

 

[Seven-Delta-FortyOne]

Since you said you checked a capacitor, that is a 3 wire pump. Your winding reading sounds like the start winding, not the main. Check BOTH.

Thanks I’ll check the start winding as well. I tested between the red and black ( T1 and T2) leads, so that should be the run winding.

I believe yellow to red (T2) should be the start windings, but I’ll double check the manual.

 

[fastline]

I did not leave it like that. That is the reading I got when I bypassed the low water shutoff. That is the reading I should get, if there was no water in the well and no low water shutdown, correct?

You should NEVER be reading LRA, ever. Low water, plugged screen, etc, never. Response should be to verify both winding readings are good to pump, then diagnose start circuit. Low water or not, you should not see LRA.

 

[Seven-Delta-FortyOne]

You should NEVER be reading LRA, ever. Low water, plugged screen, etc, never. Response should be to verify both winding readings are good to pump, then diagnose start circuit. Low water or not, you should not see LRA.

OK. That was something I was wondering about. I know the low water shutoff activates based on increased amp draw, I just don’t know how much.

Also, I found this inside the pump controller. Some reason I always thought yellow was from the start cap, it’s not, it’s red.

Anyway, I checked all the readings according to this chart, and they are perfect.

 

[fastline]

The function of your low water device is highly flawed and not correct. Now that winding resistance is confirmed, you need to check the potential relay.

 

[Seven-Delta-FortyOne]

The function of your low water device is highly flawed and not correct. Now that winding resistance is confirmed, you need to check the potential relay.

I have load side current on the start cap circuit when it tries to start.

What would indicate the low water shutdown being damaged? It appears to be doing its job.

The entire system appears to be functioning as it should, with the possible exception of a high amp reading before the low water shutoff kicks in.

In my mind, with the megger readings and ohm readings being as they should, that could point to a mechanically bound up shaft or impeller.

 

[fastline]

Whoever had the idea that high amps would equate to low water needs their head examined.....so there is that.

High amps is not acceptable. Does it move water? Did you check the potential relay? There are only TWO scenarios that would cause this. One is motor is spinning but start circuit is not disengaging due to a welded relay or coil is bad. Or motor is not turning.

Either way, high amps is a no-go.