Breaker tripping when Max pressure reached

I am baffled by a problem I am having with our deep well. When the pump is on it will make pressure to 50 psi and then trip one side of a double pole 30 amp breaker.

Some background.

We moved into the house Oct 2007. I am told the well is 600 feet and has never produced a high volume of water. The well head is about 250 feet from the house. Our area has alot of mineral deposits in the water. We do not have a water softener.

Last Nov we had to replace the line running from the house to the well head due to a short in it. I direct buried the line in the yard but never buried it crossing the driveway, just sleeved it in pvc until I could get around to it.

Last wednesday my wife said water ran out. Breaker's were fine, but the system has a sub panel by the Pressure tank in the basement. Those 30 amp fuse's were blown. I replaced them pressure started building. when it maxed out the breaker tripped. I also replaced the breaker.

I replaced the wire where it crosses the driveway due to some abrasions in it. Last night while checking things out I found the control box capacitor (Franklin Electric 1 hp 230v) oozing. I replaced that this morning with a new control box.

Fired everything up and made pressure. When it hits 50 lbs instead of just cutting out after about 2 minutes the same breaker always trips.

Could this be a pressure switch problem due to scale buildup or does it sound more like a pump failing? I don't know how old the pump is, but aqm checking.

I am heading to pick up an Amp meter to check the amperage while running.

Any ideas would be appreciated.

Pmc

Usually when this happens, it is because your pressure switch is bouncing the pump back on, immediately after the pump turns off. A check valve between the pressure switch and pressure tank may be the problem. Could also be a bad tank or a bad pressure switch. Watch the points on the pressure switch as the pump shuts off. If they pop open and then close immediately, it will cause the kind of problem you are having.

The Maximum size breaker for a 1hp motor is 20 amps. Also if the breaker is tripping, could be a ground fault or short circuit.

I just checked everything with the amp meter. It was pulling about 9.3 amps and when pressure was made the breaker tripped.

With the cover off the pressure switch I noticed the points weren't opening so with the power shut off I opened them with a flat blade screwdriver. There is some "buildup" on the points I am going to clean that off and try again.

Pmc

If the points do not open up, the pump should not shut off. The breaker tripping is the reason the pump is shutting off. Like Chris75 said, you may have a short somewhere. Check it with an ohm meter, after shutting off the power.

An update

We are getting daily rain events here and I didn't think to mention that we do have a mole problem. Resistance at the well head was good and the lines have continuity.

Today I will open up the junction box at the driveway and check resistance to try and figure out which end of the line a ground fault could be in.

Pmc

It seems awfully coincidental that the pumps breaker trips at 50 lbs each and every time. Is this what your saying? It happens everytime like that? Usually the higher the pressure, the lower the amps, so this is kind of happening in reverse.

What horsepower is this pump. The 9.3 amps would indicate a 1hp pump motor.

bob...

Another update

The pump is a 1hp 230 V.

Last week I was working through diagnosing the problem. Along the way I noticed that I would hear a click just before the breaker tripped. I tracked this to an OLD water softener that was still inline with the water system. One leg of the 230V wiring was feeding it. I unplugged it theorizing that it was part of the problem. Lo and behold the pump pressurized to 50 lbs and cut off correctly without tripping the breaker. I also dug up a section of wiring (about 4') to where I knew and old splice was.

The water worked fine, until we got a small rain event Saturday evening. Since then the breaker has been tripping. I am waiting until it gets above freezing (to morrow) to check the wire I dug up.

Pmc

We have a lot of that here in Florida. Wires get buried without conduit, moles, mole crickets, roots, ants you name it, nick the wires and the first rain comes, the breaker starts tripping.

Sounds like you diagnosed the problem yourself. Congratulations.

bob...

Final resolution

I have finally resolved the problem earlier this week. It was amazingly simple, a bad buried wire. Here's how I found it. I simply disconnected the 3 wires at a junction box in the yard and nutted them off to be safe. Then I turned power back on and checked each wire going out of the control box with a clamp on ammeter. The Black and Red wires were showing no current, but my Yellow wire was showing about .5 amps.

I got a new piece of wire and spliced it between the junction in the crawlspace and the yard junction. No problems since. The section of yard where the wire was damaged has had moles in it.

We have had rain since I fixed it but the new wire is in conduit and when I trench to bury this section (about 60 feet with a sidewalk crossing) I will dig up the old wire and encase it in conduit also.

The odd part is how the ground fault would allow the system to work some but trip when the system reached max pressure but before the pressure switch could shut off if there was any moisture present.

Thanks for all the help.

Pmc

Nice job, you are truly a knowledgable DIY'er.

The odd part is how the ground fault would allow the system to work some but trip when the system reached max pressure but before the pressure switch could shut off if there was any moisture present.

Click to expand...

I am with you on that one.