Motor overheating - now what?

Hello,

A few days ago, our well pump began to behave erratically. We lost pressure for much of the day. After hours of diagnosing, I'm pretty sure that the motor is overheating or cutting out for some other reason. Here's what I've determined:

1. When the motor starts, it runs for about 30 seconds then turns off.
2. After 2 minutes, it comes back on and the cycle continues (on for 30s, off for 120s, on for 30s etc)
3. The pressure switch remains on at all times and there is always 240V across the motor terminals
4. If I have a faucet open, the two pressure tanks drain completely
5. Overnight, with all faucets closed, the tanks eventually fill up

The motor:

4" 0.5HP 2-wire 230V Franklin Electric (2445059004) - installed ~3 years ago as a replacement for the original

The resistances between the hot wires and ground are each ~1.5Mohm (well within Franklin's range for a pump in good condition). The winding resistance is ~4.5ohm (Franklin specify 4.2 to 5.2ohm to be considered acceptable).

However, the current is definitely out of specification. The motor is rated at 5.0A (SFA Max Amp = 6.0). When the motor starts, it draws 18A and, after a few seconds, it drops to 15A. 30 seconds later the motor cuts out, presumably due to overheating. Franklin suggest that a value of 3x to 5x the rated value is a likely sign of binding.

Other info:

The well is 300' deep. The casing is 6" diameter (is it common to have a 4" diameter pump/motor in a 6" casing?) The static water level is 25'. There are frequent surges of red clay (not sand). Is it possible that it has accumulated silt causing it to have to work harder?

If I pull the pump, what should I look for once it is out, particularly the mechanical parts of the pump and the motor? Are there any resources that describe how to service the pump/motor?

I have a window of "opportunity" to pull it in the next day or so but don't want to end up in a predicament. I won't be too popular indoors.

Oh, and up until November we had a virtually useless geothermal system that ran the pump almost continuously. Since replacing it with a conventional heat pump, the demands on the pump have reduced significantly (and the house is much warmer). Maybe the almost continuous running was helping keep the pump clear.

Thank you.

John.

You've done a fine job so far.

Pulling a pump that deep is not a one man operation and if silt is built up around the pump, without equipment to lift the pump out of it you may not be able to DIY.

Either way, you won't be able to work on the wet end or motor yourself. The wet end can be fixed at a pump supply house or by a pump guy that does it. Usually the pump or motor is replaced. You can replace the motor or the wet end yourself, it's 4 nuts to separate the motor from the wet end after undoing teh pump from the pipe and cutting the motor leads/power cable.

As to not being popular indoors... ask the non cheering section ingrates how they'd like to be without water for a few days instead. And tell them they should learn to appreciate their DIYer hero that's willing to donate his time and white knuckled nervous energy going off doing something he's never even seen done before, especially on his few days off!! And saving them hundreds of dollars to boot. And if it's cold outdoors or not, I'd make'em bundle up and stand close to take notes and family album type pictures of their previously unsung hero.

Thanks for your quick reply. I have already warned my wife that she may have to assist if I do pull the pump. When it was replaced about 3 years ago, the person who did it pulled it by hand with me laying it on the ground as it emerged - at night.

I suppose I should call around some well specialists, explain what I have worked out so far and get their thoughts/estimates.

John.

In the cold that's probably a good idea. If you try to pull it, shut off the water to the house past the pressure tank. Turn off the power to the pump. Drain the pressure tank (maybe keep 3-4 gallons in a bucket for wash up) and all that will make it easier to get the pitless adapter apart.

Thanks, Gary.

I pulled the pump today. I was a bit worried about removing the cap because the four nuts were rusted and seized to the bolts. I expected them the shear but, thankfully, they rotated sufficiently to loosen the cap and it lifted quite easily. I removed the tubing going from the cap to the tanks and fractured a PVC pipe in the process (I don't have a pitless adapter). Home Depot was closed today so it remains broken. Oh well.

Anyway, I lifted the pump by myself - the best workout in ages. The pump and motor were filthy. The screen was quite gunked up. I removed the motor and the inside of the pump was also filthy. I cleaned everything with dilute bleach and a brush. The pump is a Red Jacket Grizzley and, unfortunately, you can't get at the stages. I suspect they are quite grubby, too. After putting everything back together, I ran the pump in a large muck bucket. The current was still the same as before, it got very hot and still cut out after about 30 seconds.

I lowered the pump to about 30' (5 - 8' below the static level) and got the same behavior.

In your experience, do you think the motor is okay and the pump is still binding or the other way around? If the pump is binding due to build-up on the unaccessible stages, is there anyway to remove it or is a new pump in order? Should I replace both?

It's very clear that I have an IRB problem (based on other symptoms, too) so I intend to shock the well with chlorine once I've resolved the overheating issue.

Oh, and there's now a vise grip at the bottom of the well. Ooops.

EDIT - I think I will remove the spindle that couples the motor to the pump stages and run the motor to see if the current draw drops markedly and/or if it overheats. That should give me an indication of the more likely culprit.

I would replace the entire unit. Pump and motor are probably both in bad shape. The pump rarely if ever makes the motor pull high amps. But the build up your talking about could plug some volutes in the impellers and lower the pumps ability to make pressure.

bob...

Thanks, Bob.

As it happens, I bought a new pump/motor combination this morning (I'm an impatient so-and-so) and will wire it up soon, add a torque arrestor and restrap the cable to the pipe (the original tape straps have torn). Fingers crossed, I'll have the new unit back in the well later today.

But I have a question about the chlorine shocking. I have two WX250 Well-Trol pressure tanks and cannot isolate them from the pump discharge (no valves). Are these compatible with chlorine shocking or should I find some way to bypass them (e.g., install a new valve between the pump discharge and the rest of the piping and use the hose spigot that is tee'd into the well cap? If the tanks are okay to use when shocking with chlorine, it will make things easier.

Also, perhaps a silly question, when I recirculate the chlorinated water around the house, I am supposed to open faucets to check wait for the chlorine to appear then close the system off for a few hours (or overnight). Yet, I am not supposed to let the water get into the septic system. How so if I have to run the faucets - just use a bucket and throw the water outside? I suspect it is this straightforward but want to check.

Off into the drizzle to start hooking up the new pump!

add a torque arrestor and restrap the cable to the pipe (the original tape straps have torn)

Click to expand...

You are doing two things I strongly advise against. No torque arrestors and no so called safety cable should be used for any reason. If your putting this pump on pipe that is so weak that a cable is stronger than it, your using the wrong pipe. The torque arrestors do nothing and are not needed if you tape the wire to the pipe correctly.

The tanks can take the chlorine for short periods like your doing. I just add the chlorine, rinse the well off good with 5 to 10 gallons of fresh water to get the chlorine off the pipe and wires the run the pump until I smell bleach in all cold water faucets. Let sit for at least 4 hours then flush to drain.

bob...

And so the deed is done. I finished shortly after midnight. Ugh. BTW, by "cable" I meant the motor supply wire.

I bought a new motor/pump assembly. For some reason, the last person to change it spliced the wire about 25' away from the pump (yet left me about 50' of wire on the spool he used). I tested the various resistances of the motor which were fine. I also tested the wire open-ended. To my surprise, I found that the resistance between the black hot and ground was <5M. Also, the wire between the splice and the motor was in a plastic tubing. I removed it and the wire was covered in black, slimey stuff - you could no longer tell which color was which. After a while, the resistance increased suggesting a moisture issue. With a bucket, a towel and ohmmeter I found that there was indeed a fault with the splice so I redid it.

I did end up tying a rope to the pump - this came in handy when lowering it by giving me something to lash it to so I could leave it if necessary. Because the pump is about 6" longer, I couldn't get the angle I had before to get the pump in and out of the well (I was able to feed everything through the wellhouse door. So I have to "remove" so of the siding about the door.

Anyway, I tested the pump briefly in a large bucket and it was fine. Once I had lowered the unit all the way (to 175' in our 300' well????), I fixed the repair in the line to the tanks, closed the isolation valve after the pressure switch and connected a hose to the spigot at the top of the cap. Everything worked like a charm. I ran it that way for about 30 mins. The water cleared up after about 15 mins. The pump is so much quieter than the old one - you can't tell it is running except if you open a faucet.

I went to open the isolation valve to flow water through to a large spigot outside (one of those red ones with a lever and about 3' high). The piece of copper pipe downstream of the isolation valve split and I spent the next 2 hours fixing it. Thankfully, I seem to have amassed every tool under the sun and, by 12:30am, we had running hot and cold water again. And clean dishes by the morning.

I'll be shocking the system later today.

I did end up tying a rope to the pump - this came in handy when lowering it by giving me something to lash it to so I could leave it if necessary.

Click to expand...

I suppose you used the torque arrestors also.

bob...

Ah well on average and in the cold and dark a fine job was done by Johnny and his crew. My only suggestion is that next time they start earlier in the day. And not to use an arrestor or rope, wire or otherwise.

Anyway, shocking for IRB say once a year is probably a good idea. And before someone runs a submersible in a bucket, never run a submersible pump without the pigtails being under water, they can overheat real quick in air.

An example of IRB on a pump... The teeny tiny hole in the hard rusty gunk just left of center of the pump was the only water inlet to that pump. The second picture is of another pump showing the inlet and how encrustation from IRB builds up.

Thanks for the info - those pictures are scary. At least mine wasn't like that. It looks just like the red clay we live on so we had always thought that's what it was.

Bob - in the end I didn't use the torque arrestor and it's back on the shelf at Home Depot. I would have had to remove the pipe at the pump to slide it on which I really didn't want to do.

I shocked the system yesterday. Took quite some time (2 hours or so) for the chlorine to be detectable in the house. We went out for about 4 hours and when we got back the house had a bleachy stink (hmmm). I've been running the system through a hose to a nearby water run-off ditch lined with large stones. After 18 hours, the chlorine concentration is about 1ppm. Is that normal - the time taken, I mean? Is that level okay for the septic system so we can run a couple of laundry loads and have a couple of showers?

So, the pump bit is done (I was the entire crew, too - my body has been well and truly beaten). But now I am worried about corrosion. Here's why:

The water from the well enters the house via black plastic tubing and connects to 3/4" copper tubing. It is properly bonded to the ground of the electrical supply. Over the years (15), it developed a number of pinholes. Until recently, we had a geothermal heat pump system that drew a lot of water. Its supply (via white PVC) was tee'd to the short section of copper. I'm worried about the state of the rest of the copper tubing (i.e., the whole house). When I repaired the split pipe at the well house end of things on Friday night, I was shocked to see how thin the wall of the tubing was. Trying to use a pipe cutter simply dented the copper. Compared to the usual ~1.5mm wall thickness, it was probably no more than 0.25mm and the inside had tell-tale green signs of copper salts.

The usual culprit for this is too low pH but a couple of months ago I tested the water with a pH meter (I work in a lab). I tested hot and cold both freshly drawn and after sitting for a few hours. In all cases, the pH was about 6.5.

So is the corrosion due to the IRB? Are there any instruments you can rent to measure the thickness of the tubing wall (ultrasonic etc)?

Thanks - this forum has been invaluable!

That piece of copper may be the grounding electrode for the house. Acidic low pH water is only one possible cause of pinholes, others are electrical grounds, stray voltages, high DO and CO2, bacteria etc..

With plastic water line you probably don't have a good ground on the house if that copper isn't long enough or in good dirt. Most houses with plastic water line have one or more ground rods at the meter.

I've completed the chlorine shock - it took a couple of days to get back to <0.1ppm chlorine.

So, now the next phase - pH adjustment. I performed some titrations today against NaOH(aq) and determined the amount needed to get my pH to about 7.5. I'm really struggling, though, to understand the support for and against the two main ways to do this in the field - i.e., backwashing filters vs. chemical injection. The latter seems to be quite poo-poo'd. My background/profession is physical/colloid chemistry so I don't have a problem with the chemistry and am very comfortable with the practicalities of mixing the solutions etc for the injection option. But everywhere I have looked there is specified need for a retention/contact tank and a preference for sodium carbonate over sodium hydroxide. The tank doesn't make any sense at all to me. I can understand it for chlorination to zap bacteria but not a simple pH adjustment. The kinetics are so fast that by time the water reaches the house (150' away), the reaction is over. Is there any practical evidence to justify such a tank for pH adjustment? Based on a suggested 20-minute retention time and a peak consumption of 5GPM, I'd need a 100 gallon tank which wouldn't even fit in the well-house (!) I've estimated that with a 10 gallon solution tank, I'd need to use about 1.5lb NaOH per month. I have in mind to use the pressure-driven diaphragm pump (Chemilizer). I use diaphragm pumps a lot at work and am very familiar with their reliability and servicing.

I'd appreciate any advice - thanks!