Bad pump?

[efinley]

OK guys, you've helped me a bunch in figuring out what kind of system I need for my new well and storage tank. I'm nearly done trenching and wiring but in the mean time I've got wire and pipe running above ground as a temporary solution.

The problem is that on Saturday after finally finishing the trenching to the wellhead, the last 60' were solid rock so I was digging it with a rock bucket. Probably not related...

So after digging all day I go in to take a shower and there's no water! The pump and well have been working fine for 3 weeks now (just started using them) but now getting water is sporadic. It is possible the well isn't recharging and the pumptec box is doing what it is supposed to, but yesterday we used maybe 100 gallons of water total before the QD kicked in.

I have a Goulds 5GS10 1 HP pump set at 380' with a hypothetical static water level of 80'.
When the pump is pumping it is pulling 9.6 amps off one leg of the supply.
After the QD kicked in I hooked the ammeter back up and flipper the breaker on. The current would oscillate between 9.3 and 10.4A and then in under a minute the current went to 0 as the QD kicked in again. I know the QD kicked in because I still had 240V going to the QD box.

I can't find my pump in the Goulds tables but based on other 1 HP pumps it seems my current is a little high. What do you guys think?

BTW I'll mention this because of another thread I read (I promise I tried to do my homework before posting), this pump was set about 3 years ago, we just got around to using it now that the pump on our old water system died. So it sat unused for 3 years with only occasional use as I would haul a generator out just to mess with it.

Thanks!
-Eric

 

[Reach4]

There appears to be a calibration process available. http://franklinwater.com/products/drives-protection/residentiallight-commercial/pumptec-family/

 

[Sponsor]

 

[efinley]

Sorry to sounds like an idiot but... I've been to that site many times and looked at most of the docs but haven't found the calibration process (much to my frustration). Which doc are you looking at?

 

[Reach4]

Sorry to sounds like an idiot but... I've been to that site many times and looked at most of the docs but haven't found the calibration process (much to my frustration). Which doc are you looking at?

There may be more than one version, but http://lib.store.yahoo.net/lib/kingpumps/FRA-CTL-QD-PumpTec-Bulletin.pdf has the procedure for one.

 

[efinley]

Thanks for that link! I just did the field calibrate to see if that does anything. While I was at it I put the ammeter on again and I was getting 10.0 amps at 30psi and it dropped to 9.5 amps at 50 psi (the cut off setting).

I also figured out the charts for the pumps. I was confused because I have a 5gs10 pump, but then the manuals switch to the motor model which I guess is a M10412. The manual says 2.0-2.6 Ohm between B-Y and 9.3-10.4 R-Y. I measured 3.9 B-Y, 12.4 R-Y. If I account for the wire (380' of #10) in that adds .81 (380*.214) I'm still a little high.
B-Y = 2.8-3.4 vs 3.9 (expected vs actual)
R-Y = 10.1-11.2 vs 12.4 (expected vs actual)

So they are both about 10% too high. Is my pump bad?

Thanks,
Eric

 

[Valveman]

Oscillating amperage makes me think you are pumping air. But with 300' of water and a 5 GPM pump in the well you should be able to pump hard for over an hour before the well runs dry. Disconnect the pumptec and monitor it manually for a while to see what is happening.

 

[efinley]

I was thinking of doing exactly that... If I set the pumptec to the "field calibrate" mode does that disable the pumptec? This is in one of those damn integrated boxes so you can clamp onto anything in the box, and I'm not 100% sure how to disable it. If not I suppose I can just jumper around the pumptec brick... I'll try that if the field calibrate fix doesn't fix it.

I sure wish I knew about the 1/4" tubing trick when my well was installed. At least then I would know if I had a water problem or a pump issue! Oh well... Or does someone have a cool idea how to get 380' of 1/4" tubing down an existing well?

 

[Reach4]

The manual says 2.0-2.6 Ohm between B-Y and 9.3-10.4 R-Y. I measured 3.9 B-Y, 12.4 R-Y.

The generation 1 column says 2.2-3.2 ohms and 11.3-12.3 ohms. That gets you closer.

Plus, a tw0-wire ohmmeter can have significant lead and contact resistance. The wire may meander a bit. The meter may not be quite right in calibration.

I don't know about those motors, but it sounds pretty close.

Regarding the field calibrate, as I read it, the unit remembers the current draw during the first 15 seconds while you are pumping water. And then looks for a later percent reduction in that current to indicate that you are out of water.

 

[Valveman]

I was thinking of doing exactly that... If I set the pumptec to the "field calibrate" mode does that disable the pumptec? This is in one of those damn integrated boxes so you can clamp onto anything in the box, and I'm not 100% sure how to disable it. If not I suppose I can just jumper around the pumptec brick... I'll try that if the field calibrate fix doesn't fix it.

I sure wish I knew about the 1/4" tubing trick when my well was installed. At least then I would know if I had a water problem or a pump issue! Oh well... Or does someone have a cool idea how to get 380' of 1/4" tubing down an existing well?

You can clamp an amp meter around one of the wires at the breaker or the pressure switch

 

[efinley]

I did clamp it back at a junction box to get the readings, I'm just annoyed by the QD box since I have to walk back and forth to fiddle with the box and then come back to take readings. And I'd really like to get a voltage reading at the pump to see what kind of wiring loss I have, I can't do that without rewiring the whole damn thing.

BTW my ohm meter is a fairly nice Fluke and when I shorted the leads it was .2 ohm, but the point is taken... I'm in the right ballpark.

 

[Reach4]

And I'd really like to get a voltage reading at the pump to see what kind of wiring loss I have, I can't do that without rewiring the whole damn thing.

If you are motivated enough, there are techniques. Study up on a 3-wire ohmmeter as a hint. Few would even attempt that. But you can read up on it.

On your wiring, 1000 ft of #10 is close to 1 ohm. You have the round trip to the pump, and the wiring to the junction box. Your 0.81 ohm number seems to account for the trip down and back from the pitless to the pump, but maybe not for the extra wire to+from the junction box.

 

[efinley]

This was taken at the pumptec box right at the well head, so it really is only 380' down and 380' back.

 

[efinley]

Valveman,
Why doesn't anyone make a dry pump protector that includes a flow meter? Why does everyone try to measure small differences in current to estimate flow when they could measure the flow directly? Is it simply cost or is there a technical reason. After spending thousands on getting a well up and running another couple hundred for a flow meter seems pretty trivial.

 

[Valveman]

Valveman,
Why doesn't anyone make a dry pump protector that includes a flow meter? Why does everyone try to measure small differences in current to estimate flow when they could measure the flow directly? Is it simply cost or is there a technical reason. After spending thousands on getting a well up and running another couple hundred for a flow meter seems pretty trivial.

Differences in current are directly related to differences in flow, so that is a very dependable way of looking for dry run conditions. There are some irrigation systems that use a flow meter. If the meter is spinning and the controller has not turned on any sprinkler zones, the system knows there is a leak somewhere and can either close a valve or shut off the pump.

Flow switches have been used for years to detect dry run or deadhead conditions. They work ok, but flow switches are not known for dependability. They get stuck, they wear out and slap around, and they just don't work very good at really low flow rates. Plus you have to use a circuit that starts the pump with a timer, gives time for the contact in the flow switch to make, then times out to let the flow switch continue making the circuit. Otherwise you can't get the pump to start because the flow switch is down.

Low pressure cut off switches work about 95% of the time as well. But the most reliable way to detect dry run is amperage times the power factor, which is what the Cycle Sensor does.

 

[efinley]

I recall reading from you that a pumptec has trouble with things like a dole valve because the current is near the dry run current. What is the difference in current between the pump dead heading (sort of a dole valve scenario) and dry running?

I'm not doubting you, I'm trying to learn and figure this all out.

 

[Reach4]

Differences in current are directly related to differences in flow

In this case, a 5 GPM 1HP pump would be expected to draw its maximum current with an 80 ft head, I think. In that case, the pump is operating off of the right of the curves or on the left side of the table. As the water dropped, the current would drop.... not so much as it would if the pump started sucking air. I don't know the numbers to expect.

You could reduce the current some if you raised your water pressure to 50/70 with the thought that you could go back to a lower pressure if the water ever dropped much. OK, it is a small amount, but its free and reversible. Remember that if you change your pressure switch setting, you need to change the air precharge also.

In the attached graph, add about 138 ft for 60 PSI water pressure. So with water 80 ft down, at 60 PSI up top, the head the pump sees is about 198 ft.

 

[Valveman]

I recall reading from you that a pumptec has trouble with things like a dole valve because the current is near the dry run current. What is the difference in current between the pump dead heading (sort of a dole valve scenario) and dry running?

I'm not doubting you, I'm trying to learn and figure this all out.

I think it has a lot to do with what kind of motor you have. Some will have no load amps about 40% of max, while others will only drop and amp or two. But there is always a noticeable drop when the pump runs dry. Power factor also decreases when the pump is running dry.

 

[Boycedrilling]

I bought a amperage data logger a couple of months ago to help diagnose a problem with a Berkeley 3 hp submersible with a cycle stop valve . The pressure switch was set at 40/60 with a 50 psi CSV. The data logger was set to log once per second. Starting amperage was around 86 amps. Running current at 40 to 50 psi was around 17 amps. Then when the CSV started regulating, the amps dropped to around 14.5 amps and couple go as low as 13 amps. When I get back from Cabo, I'll see if I can post the graph of the amperage draw.

The problem we were trying to find ended up being an intermittent sticking of the start relay. If the start relay sticks the amps stay at 86?amps for over one second and trip the overload in the start box. Pentair has had a problem with the start relay in the 3 hp box, and are now on their third supplier.