Pumps cycles every few minutes

Joel McElrath

Joel McElrath

New Member
Messages
6
Reaction score
0
Points
0
Location
Granbury, Texas
I have a NEW 1 h.p., 230 volt, 2-wire, 20 GPM pump. It is connected to a sprinkler system through 300 feet of 2" PVC. When the pump comes on, it cranks out about 20 GPM. After 3 or 4 minutes, it shuts off. I'm not sure if it is completely off because a trickle keeps running for awhile. I think the trickle might just be residual water draining from the pipe because the last 150 feet slopes down gently.

There are no pressure tanks or switches in the circuit, just a wire running from the breaker to the pump. The electrical wire was already buried when I bought the place. It is about 370' from the breaker box to the pump, but the wire probably does not go straight to the pump because of obstructions. It could possibly be over 450' from the breaker to the pump. Would this distance be enough so the resulting under voltage would cause the thermal overload protectors to shut off the pump?
 
Last edited:
Quite possible unless it ran previously without interruption.

What is the wire type and gauge?

What is the voltage at the pump when running?

What is the amp draw of the motor running?
 
Above ground pump?
Is it possible it's running out of water?
Why don't you go to where the pump is and listen to it so you can tell us if it's stopping or sucking water.

Rancher
 
Between 400 and 630 feet you should be using at least #10 gauge wire. If it's a smaller gauge, the pump could heat up and trip the overload.

The thing to do is listen to see if the pump stops running when the water does.

bob...
 
The pump is new. The wire is 12 gauge. I'll recheck today, but the amps has been about 9. Maybe I'll check the amps when it quits pumping. 0?
It is installed on its side inside a sleeve, in a 100' wide, shallow river. The pump lays in about 8" of water with an inch or two of water over sleeve. Supply is no problem.
 
Last edited:
Wire acts like a resister (think heating element). The longer it is, and the more current you ask it to carry, the less voltage you get at the motor end. 12g will "lose" too much voltage to heating the wire. This makes the pump try to draw more current at the lower voltage, and it can heat up. You might be seeing the pump's overheat self-protection circuit engaging which is why the pump turns off after awhile.

As noted earlier, you should measure the voltage to the pump while it is running, check it at the supply end, and note the voltage drop. Does the pump get enough voltage while it is running to meet the minimum specs? If not, you need a larger gauge wire so it can more easily pass the voltage (less resistance loss).
 
Voltage Drop

OK my calculations, 1HP = 746 Watts / 240 Volts = 3 Amps

Voltage drop over 450 feet for 12 AWG copper is 4.481 volts

Voltage to the pump should be 235.5 VAC,... So I'm going out on a limb here but I'm guessing that if there is enough voltage and power to spin that motor up and get it running, it should continue without going into thermal overload.

I vote either the pump was bad out of the box, or the well is being overpumped.

Joel, what were you using for a pump before you put this new one in?

Source for calculations: http://www.powerstream.com/Wire_Size.htm

Rancher
 
Rancher,

That 1hp motor if it's a Franklin will pull 9.6 amps when putting out a good flow of water, 20 gpm in this case. This is 2208 amps at 230 volts. He called it a two wire pump so I have to assume it's a submersible. Since it's new, it could have either a Franklin, Tesla or the brand new team ITT/Pentair motor. I don't know what the new ITT/Pentair motor pulls, but it should be close to the Franklins amp draw. If he has the Tesla, it probably won't last more than a week anyway. That was my experience with them when Myers (Pentair) was substituting them for the Franklin while trying to get their new motor off the press.

bob...
 
Bob, you're right

But that 9.6 is S.F. Amps so that's the max the motor should pull under varing voltages, normal full load Amps is 8.2.

So Voltage drop is: 12 volts

12 AWG is rated 9.3 Amps/1000 feet max for a transmission rating, which this would be, so the wire itself is not over it's limit.

Franklin Electric says their limit on the 1 hp 2/3 wire 230 volt motor for 12 AWG is 400 feet. So it's probably at or just over the limit, I still think it should work.

Of course we don't really know how deep the pump is either...

Rancher
 
Almost all the 1hp motors I amp out here (which is what most of these drillers put in for some reason) are pulling 9.6, right at max. It's rare that one will pull much less. Most pump manufacturers use all the amps the motor will make by building the pump to the motor.

I agree with the 400 feet in Franklins book, but they are the ones that have to warrant the pump motor, so I think they tend to be a bit conservative.

And your right, you have to add the depth of the pump to the overall length.

bob...
 
The pump lays on its side in a river--barely, but completely covered with water. The river is 150' wide and the water is nearly still so the pump is always in the water. I measured the voltage at the pump (running) and got 239 volts. Amperage varies. At start, it was about 8.4 and pumping 1 to 2 GPM. After 10 minutes it kicked up to 9.4 and began pumping at least 20GPM for a couple of minutes, then fell back to a trickle and 8.4 amps. Five minutes later, it kicked back up to 9.4 amps, really pouring out the water. This lasted 5 or 6 minutes, then same old thing--back to a trickle. By now the amps are jumping around between 8.0 and 9.0 as fast as the meter can change.

I'm kind of starting to believe that it is not the wire, but I have no idea now because it seems to be inside the pump.

This is a Betta-Flo submersible so I think it is a Franklin motor.
:confused:
 
Last edited:
So it's still drawing near max amps but pumping little water... something bad in the pump section? I'm sticking to my "bad out of the box" statement.

Rancher
 
You said it is barely covered with water. Chances are, it's hot deep enough in the water to keep the inlet from sucking big gulps of air. Being horizontal, it's not real easy for the pump to rid the impeller stack of the air so it takes a while to start pumping again. If it's doing 20 gpm, it is not likely a bad pump.

Besides I sell Betta Flo's, and they Rock. And they do have Franklin motors, unlike Goulds, Sta-Rite, Red Jacket, Aermotor and Berkley to name a few.

bob...
 
I appreciate your responses very much. When I look at the pump, I don't see any whirlpooling or even any water movement, but I am going to remove the sleeve entirely. I was a bit suspicious of it from the beginning. It is the standard piece of 4" PVC but the outlet in the well seal is off center which makes the pump crooked in the sleeve. It also has a 4" to 2" reducer on the bottom for attaching a filter. I removed the filter when I first noticed the problem and it seemed to help a little. I'll bet there is some super turbulence inside that sleeve. In you opinion(s), how important is the sleeve? Most of my neighbors have this same setup (horizontal submersibles) and only one has a sleeve.
I'll post again when I get the sleeve off.
 
Last edited:
There are differing opinions on the sleeve. For my money, leave it off. The inlet to the pump can still pull air if it's close to the surface of the water. I'm not real sure what bushing it down to 2" would do at 20 gallons per minute. But it's not a good idea to pull a vacuum on a submersible pump. It could cause the same condition as upthrust, which can nuke the impellers.

bob...
 
Try it without the sleeve, Franklin Electric recommends sleeves for any pumps in an open body of water, although I would think the pump pulling water in from all around it would provide enough water movement to cool the motor.
If the motor is cocked, you need to add the centering bolts show in the attached diagram.


Rancher
 

Attachments

  • flow_inducer.gif
    flow_inducer.gif
    16 KB · Views: 966
NO SLEEVE. NO PROBLEM. I removed the sleeve and the pump hums along at 9.4 amps, 239 volts, cranking out 20+ GPM without pause. I plan to redo the sleeve like the drawing from Rancher and saw off the 4" to 2" coupler. The water gets pretty warm in mid-summer so the sleeve might be helpful. If this causes a problem, I'll know it because I know the pump and electrical wire are okay.

Right now, I think I'll sit down and have a cool one as a toast to all those who helped me with this problem.

Thanks again.
Joel
 
Bob (Speedbump) sells a filter bag you can put the pump in when you get the sleeve re-built.

Rancher
 
I never quite finished with the well when the temperature fell below freezing and stayed there. What I finally did to the pump was to cut the top off the filter (the part where it reduces from 4" to 2"). This permitted me to replace 4" to 2" coupling on the bottom of the sleeve with a straight 4" coupling. The filter fit nearly perfect into the 4" coupling so I wound up with a straight through connection instead of the 2" constriction. The pump now works as intended, cranking out 20+ GPM, and the filter 2" filter connection was the only problem.
 
You must log in or register to reply here.

Similar threads

J
Goulds 3AB2 booster pump issue
Replies
2
Views
506
Valveman
Valveman
K
Solution for existing pump electrical problem.
Replies
4
Views
8K
kinnison
K
D
Is The Pump Running Dry?
Replies
17
Views
2K
DS1
D
J
Electric Bill Tripled! New pump size recommendation please.
Replies
4
Views
4K
Valveman
Valveman
G
Well pump wiring question
Replies
3
Views
4K
Fitter30
Fitter30
Back
Top