Replaced water well pump , ran 3 weeks , same issue as before or ??

westbranch

Sorry but not really a Solar powered pump right now, I need more PV to run it eventually.
Well 305 feet deep, static level 25 feet. , 64 grains of hardness, 2 points of iron too.
3/4 hp submersible , new installed 3 weeks ago.
Previous 240 V pump ran > 15 years, stopped running of 'old age'. Checked CB and it was tripped. Used  Clamp meter and pulling ~75A. No tear down to identify exactly what was locking the motor....
New pump now drawing approx the same Amperage  > 73A   and tripping breakers after 3 weeks.
Run time is probably much less than a 'normal' house as 2 seniors and we had been away for  a 6 day Easter long weekend.
Only thing that should have used water is the water softener.

Any suggestions as to possible causal agent that killed 2 different pumps in under a month? 
Power surge?
Uneven power on 2 legs? ( we are the second last house on the line)
As it is a new pump I would have expected the failure , if faulty construction, to have been in the first few days....NO?

Any suggestions welcome.

Estragon

I wonder if there's an issue with the breaker or wiring? Pulling large current might have heated up a connection to where it's now causing high resistance?

If there was a problem with something plugging the pump in the hole or a restriction in supply hose, I'd think the current draw wouldn't be higher than ~LRA.

BB.

A long shot--It could also be a failed starting capacitor (shorted or open). Relatively easy to check if at top of well head (and not installed in motor).

-Bill

westbranch

Well, there is a possibility that the CB being faulty, it has not tripped much in the time we have been here, just post construction in '79...  ..  Will have to check that out...  pulled ganged 15A  Federal CB, no obvious poor connection indicators, will replace it just in case.
The  pressure switch  was changed out with the pump. 
All new wire from the top of the casing (8 foot well pit ) to the pump.

The only original segment is underground from the house 50 +- feet to the pit..

jonr

Maybe the well sometimes runs dry and the winding insulation fails (causing shorts).  Surges seems statistically unlikely.  I don't think there is such a thing as uneven power on legs with the typical residential split phase system in the US applied to a 240V motor.

cow_rancher

westbranch said:

Previous 240 V pump ran > 15 years, stopped running of 'old age'.  Used  Clamp meter and pulling ~75A. No tear down to identify exactly what was locking the motor....
New pump now drawing approx the same Amperage  > 73A   and tripping breakers after 3 weeks.
Run time is probably much less than a 'normal' house as 2 seniors and we had been away for  a 6 day Easter long weekend.
Only thing that should have used water is the water softener.

Uneven power on 2 legs? ( we are the second last house on the line)

The pump was bad in both instances, 75 or 73 Amps on a 15 Amp breaker... the breaker was doing it's job.  Run time, OK how about cycle time, is your bladder tank waterlogged, rapid cycling of the pump will kill it.  As jonr pointed out there is no such thing as split legs for a 240 volt pump, measure the voltage at the well pit, and tell us what it is, and it could be running dry, or sucking sand, or it may have just been a pump built on Monday Morning.

Rancher

mike95490

If it wasn't the rainy season, I'd second the dry well as a cause of failure.

mcgivor

Electrically a voltage sag would cause a motor to draw more current thereby heating, causing premature failure, if the utility was at fault  there would be other signs such as lights dimming. Additionally a bad splice could cause similar effects, connecting a load greater than the pump at the well and monitoring voltage would reveal if there is a wiring issue, the breaker would not be the cause, just a symptom. From the description it sounds possible the pump may have run dry.  
How deep below static is the pump? To measure static level  I use a fishing weight and float, the float just large enough for buoyancy, weight enough to feel, when it hits the water the line becomes slack pull up and measure. Worked so well I tied the line to a lever arm micro switch and incorporated it into the control circuit to disable the pump when or if the water level nears the pump. 

peakbagger

There is device called a pump protector you can install on the capacitor box, that monitors current and voltage which shuts the pump off when the pump is not running normally. It will usually catch things like running when dry, under and over voltage and overrunning when there is broken pipe in the house. It not super sophisticated but better than nothing. On my Franklin box, I just plugged it in a mating receptacle in my capacitor box and that was it.

westbranch

Thanks for all the comments.
The installer put a new pump down the casing and is  going to dismantle the failed (new) pump.... when he arrived to assess what had happened he was really trying to nail down the cause of failure.  He installed another  MYER 3/4 hp submersible pump which he has had good luck with for the last 7 years, having no early (within first month) motor failures...
BTW I found out that (almost) all brand name pumps sold up here all use FRANKLIN submersible motors now.
They checked the buried cable section for conductivity and was happy with it, no obvious loss of power to that point. 240V...
The 270 feet of #10 'drop' wire was brand new with first replacement pump...
Flushed the system liberally to get rid of the iron deposits released by disturbing the water line  and fittings again.  This had been done with the first new pump but not as long, as I remember...
Next to the basement, we were discussing the current system  for a few minutes and suddenly he wanted t know how long since the system had been in use, servicing etc.  He was onto something as he noted that it took too long for the pressure to rise to max , 60 PSI.... How old was the system and service history?
We have had a PETWA  air injection type Iron filter since 1990, We have very hard water!  64 Grains plus 2 points of iron. 
4 years ago new Pressure tank and PETWA water softener were installed ( when (98%)  Korean Hi Efficiency condensing DHW heater failed for 3 rd time).. along with a new 98% Lennox condensing Nat Gas furnace and an Envirosense condensing DHW heater. Most of the plumbing was replaced and all components were serviced.
The bladder on the pressure tank sprung a leak about year 1 1/2 .... Cause a factory defect.  Second unit is still OK...
Then an Ah Ha moment.... after the first new pump had been installed we had not removed the coarse filter (cleanable) sitting just before the air injector,... opened it up and discovered the 4 inch long x 3/4 inch diameter screen was full of flakes and a mushy slimy slurry of finer oxidized Iron...  cleaned that out and the P. Tank pressure tank charged as normal. 
It took almost an hour of flushing untreated water onto the lawn before the water was flake free. 
We suspect the source oxidized iron deposits on the 90' iron well casing in addition to the 250' of PVC liner  and inside the water lines from the pump to the house to be the cause of too much back pressure on the pump itself. 
A pump postmortem is to be done today or tomorrow.

ADD: well is 305 feet, last 5 feet in coarse sand, static level now at 25 ' from surface, pump at 275' approx 30 ft from bottom,.
top 90' iron pipe casing,  250' of PVC casing to bottom.
Well driller , old style thumper, could only bail test at 30 gpm from ~50' down, inflow is > 30

jonr

> cause of too much back pressure on the pump itself.

Or probably more precisely, created too low a flow to provide proper cooling.   In retrospect, measuring either amps (low at restricted flows) or flow rate (run time to fill pressure tank) would have been wise.

cow_rancher

jonr said:

> cause of too much back pressure on the pump itself.

Or probably more precisely, created too low a flow to provide proper cooling.   In retrospect, measuring either amps (low at restricted flows) or flow rate (run time to fill pressure tank) would have been wise.

This is exactly why you should never consider using a Cycle Stop Valve on a home well system, it restricts the water flow to keep the pump running under the mis-belief that cycling is the major cause of pump failures, it is very heavily marketed on the Plumbers site out of Seattle WA.

Rancher

Dave Angelini

Erric, what kind of roof do you have??



Use rainwater

westbranch

Dave, it is Duroid ... but it has to be replaced this year.  We were going to do it last yr. but the fires and evac knocked it off the list.. we are thinking of metal for more than 1 reason... soft DHW water would be great , I will work on SWMBO...