Testing a well that hasn't been used in a while

[Watson524]

Hi there,

We tore down a mobile home recently but the electric was disconnected about 5 years or so ago so the well hasn't been run in that long. Thinking about turning it into an RV site since we have electric pole/wall/septic onsite already.

The well was installed in 1973 when my parents got married and all I know about it is that it's about 600 feet deep. Pitless adapter style. When the mobile home came down, we left the black water line long and have access to the 2 wires coming from the well. Thinking to see if the pump is still ok, I'd hook it up to our portable generator which has a 220v plug option. Any reason that won't work? Only thing I'm not sure if is the amps needed as I think the generator has a 30a breaker in it (I'd have to check).

I just want to see if water comes out before I get into sanitizing/shocking it etc.

thanks!

 

[Reach4]

How far down is the water in your area typically? That is aimed at estimating the power required. 600 ft deep well seems deep for PA. County may have records.

How many wires go down the well, and what are the colors? That is aimed at the odds that you have a two-wire pump, or a 3-wire pump (which needs a control box).

Also, if you can measure the wire-to-wire resistances, that can help even better. Expect resistances on the order of 4 ohms, give or take for the power wires.

A generator normally needs to be upsized from the nameplate readings to get the pump started.

 

[Sponsor]

 

[Watson524]

How far down is the water in your area typically? That is aimed at estimating the power required. 600 ft deep well seems deep for PA. County may have records.

Our old house across the street is about 225', the house we're in now which is using the same well as the old farmhouse that used to be here my dad used to say was about 300'. 600' is definitely deep for around here but my parents always told me when they drilled it when they first got married, my dad would call my mother at school every 50' to say "do we keep going?" and she'd say "what choice do we have?". My husband is a geologist and he said the 600 doesn't surprise him given how fast depths can change so..... I do know the company that drilled it originally and they are still in business so I was actually going to call and ask them. Definitely the county won't have records of something like that up here.

How many wires go down the well, and what are the colors? That is aimed at the odds that you have a two-wire pump, or a 3-wire pump (which needs a control box).

2, it's like 3 wire submersible pump wire today, but only has red and black markings on the yellow shrouding so I'd call it a 2 wire. I happen to have some length of the 3 wire submersible pump wiring (black/red/green) so my plan was to wire nut 2 of those wires into a plug for the 220 port on the generator.

Also, if you can measure the wire-to-wire resistances, that can help even better. Expect resistances on the order of 4 ohms, give or take for the power wires.

So literally just get the ohms going from the red to the black coming out of the well? I can definitely do that tomorrow and report back (dark comes too early these days).

 

[Reach4]

So literally just get the ohms going from the red to the black coming out of the well?

Yes.

Zero your ohmmeter if you can, or note the resistance shown if you just touch the leads together.

Also, any recollection of how far down the pump is? Many wells have a much higher water level than the well depth. Anyway, take the ohms.

 

[Watson524]

Yes.

Zero your ohmmeter if you can, or note the resistance shown if you just touch the leads together.

Also, any recollection of how far down the pump is? Many wells have a much higher water level than the well depth. Anyway, take the ohms.

Nope never heard where the pump landed only the drilling depth. I guess I always thought pumps sat towards the bottom of the well vs higher up. If you sit it higher up, wouldn't you have to be worried more about refill rate in the well or do they test all that when they set the pump level?

 

[Reach4]

Nope never heard where the pump landed only the drilling depth. I guess I always thought pumps sat towards the bottom of the well vs higher up. If you sit it higher up, wouldn't you have to be worried more about refill rate in the well or do they test all that when they set the pump level?

They often test, and see how far the well draws down. Then add margin.

The resistance will be the sum of the wire resistance plus the pump resistance. Also note the wire AWG if you can read it, or estimate the size of the wire if you are familiar with wire sizes.

 

[Watson524]

They often test, and see how far the well draws down. Then add margin.

The resistance will be the sum of the wire resistance plus the pump resistance. Also note the wire AWG if you can read it, or estimate the size of the wire if you are familiar with wire sizes.

Ok sounds good. I think I have enough jacket to read the AWG but if not, I can figure it out based on the size. My initial gut tells me it's 12/2 given it looks about the same as the roll I have in the barn that I'm 99% sure is 12/3 but I'll confirm around noon tomorrow when I get down there where the well is. thanks!!

 

[Watson524]

Ok here's what I learned. It's 6 strand copper wire. Measures 0.111 to 0.115in (3mm). I can't see the markings on the jacket but that should be 10ga if I have the right table. It definitely is bigger than my marked 12/2 wire (so if I test the well, I'll switch the plug to a length of 10/2 that I have vs using the 12ga).

Across the wires from the well the resistance is 5.3 to 5.4ohm. Touching the 2 probes together is 0.6ohm.

I had forgotten at the time but I think I remember something about calculating length of cable on a spool by knowing the factor / 1,000 ft based on wire size and doing a ratio, is that what we're getting at?

So 5.4 - 0.6 gives 4.8 (I think we subtract out the resistance caused by the probes themselves, right?). I looked up some tables and I get different numbers for the 10 awg wire and it's temp dependent (tho I don't know if temp matters given it's well below ground?) I see 10awg at 1 ohm/1,000', but as low as 0.92phm and as high as 1.2ohm.

Then do we need to assume whatever number is divided by 2 because it's 2 lengths of wire, down to the pump and back up? If my 4.8 is right and I use 1 ohm / 1000' I get WAY too many feet so I guess I didn't pay enough attention in physics class or wherever I heard about doing this Unless stranded vs solid wire makes a difference in the resistance factor, which would make sense to me.

 

[Reach4]

For DC, I think there is no difference between 10 AWG stranded. Difference at 60 hz is trivial.
So these are rough. The Franklin AIM manual gives a range of resistances of the 2-wire motors.
So it is plausible that you have a 3/4 HP motor.
Franklin recommends a 3 kw , 3.75 kva, generator for a 2-wire 3/4 hp pump.

 

[Watson524]

Thanks! My generator is 13.4 kW max so it sounds like I'm OK there but I don't know the kva on it. Is that something I can calculate based on other info so I can know if it's OK to proceed with my test of hooking up the 2 wires from the pump to the generator?

Based on the resistance, are we able to figure out depth of pump like I thought or no? Know idea (if I can proceed with the test) how long it would take for me to see water coming out.

 

[Reach4]

Thanks! My generator is 13.4 kW max so it sounds like I'm OK there but I don't know the kva on it. Is that something I can calculate based on other info so I can know if it's OK to proceed with my test of hooking up the 2 wires from the pump to the generator?

The KVA rating will be bigger than the watts rating on your generator.

 

[Valveman]

Check the amps when you turn it on. 7 amps is a 3/4HP. 9 amps is 1HP. If it pulls high or low amps and there is no air blowing out the pipe, turn it off quickly. I don't understand your ohm test? Does any of the three wires ohm out as a ground wire?

 

[Watson524]

Check the amps when you turn it on. 7 amps is a 3/4HP. 9 amps is 1HP. If it pulls high or low amps and there is no air blowing out the pipe, turn it off quickly. I don't understand your ohm test? Does any of the three wires ohm out as a ground wire?

Do you mean across the 2 wires coming from the pump when we turn the generator on?

The pump only has 2 wires going to it. I thought the ohm check I was asked to do was maybe to determine depth of pump.

 

[Reach4]

The pump only has 2 wires going to it. I thought the ohm check I was asked to do was maybe to determine depth of pump.

Did you understand the right part of the spreadsheet snip I posted in #9? If there is a question about one of the columns, let me know.

The data is imprecise. We don't know the actual resistance of the motor, but we think we have a range. Your resistance reading is imprecise because your typical ohmmeter is not that good at measuring low resistances. So the calculations cannot give a precise depth. If the motor was a 3-wire motor, we could know much better. Yet I think these limited-precision numbers have value. Just don't assume too much precision.

If we assume that this is 10 awg, I think it is reasonable to presume that this is a 3/4 hp motor set deep or a 1/2 hp motor set not so deep. That negative reading in red is an impossible condition.

 

[Watson524]

Did you understand the right part of the spreadsheet snip I posted in #9? If there is a question about one of the columns, let me know.

The data is imprecise. We don't know the actual resistance of the motor, but we think we have a range. Your resistance reading is imprecise because your typical ohmmeter is not that good at measuring low resistances. So the calculations cannot give a precise depth. If the motor was a 3-wire motor, we could know much better. Yet I think these limited-precision numbers have value. Just don't assume too much precision.

If we assume that this is 10 awg, I think it is reasonable to presume that this is a 3/4 hp motor set deep or a 1/2 hp motor set not so deep. That negative reading in red is an impossible condition.

Huh, I was on my phone when I read your last note and the tablet didn't show up. Now that I'm back in the house and reading on my computer, I see it. I would agree that a 3/4 seems most likely given what I've always been told about the depths of this well being 600ish feet. Guess after I get done my next meeting, I'll hook up a 10awg patch cable and see if the pump does anything as far as producing water. Just no idea how long to expect it to take for water to actually flow. And it just dawned on me, this generator used to go into a secondary panel in the house I'm in to run the well, refrigerator, AC, and many rooms of lights and outlets so it definitely should be ok with just a pump on it.

 

[Valveman]

but only has red and black markings on the yellow shrouding so I'd call it a 2 wire.

Usually the center one has no marking because it is yellow already. If there are three, one would show a short to ground if it is a 2 wire, but not on a three wire motor.

 

[Watson524]

Usually the center one has no marking because it is yellow already. If there are three, one would show a short to ground if it is a 2 wire, but not on a three wire motor.

This cable has a yellow jacket, inside it are 2 10ga wires. One with a red stripe on the side of the yellow and one with a black stripe. The pump doesn't have a ground as I understand it and wasn't uncommon for an almost 50 year old pump

 

[Watson524]

Check the amps when you turn it on. 7 amps is a 3/4HP. 9 amps is 1HP. If it pulls high or low amps and there is no air blowing out the pipe, turn it off quickly. I don't understand your ohm test? Does any of the three wires ohm out as a ground wire?

I hooked it up and ran it had no air movement in the pipe so I shut things down because I didn't want to goof something up. I thought with amp testing to you had put the meter between power and the load so I'm not sure where I'd put the meter probes to properly test. My meter I believe only goes up to 10a so if it happens to spike high, wouldn't I blow the meter too?

 

[Fitter30]

Need a clamp on amp meter not one wired in line. Pump motor would blow up your amp meter. Harbor Freight carries clamp on for $30 might even find one at walmart. Pump is 230vac not 120vac.

 

[Watson524]

Need a clamp on amp meter not one wired in line. Pump motor would blow up your amp meter. Harbor Freight carries clamp on for $30 might even find one at walmart. Pump is 230vac not 120vac.

Ah ok that makes sense. Yeah I'll have to pick one up. Handy to have anyway. Either way, I am going to call the company that put the well in and see what they say. Frost is about 4' around here so in theory I could pull the pump but I have no way to coil all the pipe that would have to come up with it so I'll have to leave that to the pros