Intermittent pump on well.

[Sans1964]

Ok I have a 380 foot deep well a new 3 wire 1 hp gould at around 340 feet . Wster at Round 150 from well top. new pressure switch 40/60, new breaker in the panel, new fuses in disconnect. Pressure tank at 38 psi. Problem is randomly no water. Could be days before it happens . Throw the switch a bit later I can turn it on and get pressure. This can happen even after 24 hours of no water use. The system holds pressure and water is clean. I think the pump is going into overload, I measure around 7 amps at running. I should note that the pump was installed 2 weeks ago. Previous pump exhibits same symptoms.

TIA
Scott

 

[Reach4]

Did you get a new controller box?

 

[Sponsor]

 

[Sans1964]

Did you get a new controller box?

Actually no. The previous one didn't have one and neither does this I was umder the impression that a 3 wire haf yhat yhe start up coil built in

 

[ACWxRADR]

Scott,

I was simply checking in on my own post to see if there were replies and I read yours. I am not a professional when it comes to submersible pump systems, but I am a fairly good troubleshooter when it pertains to electrical and mechanical systems.

You state that the pump is new, the pressure switch is new and the circuit protection (breakers and fuses) are new. The water depth is acceptable and the check valve is holding as you do not lose prime. Tank pressure is set appropriately (38 psi for 40 psi cut-in on the pressure switch). All this is excellent and you have covered the major components.

So the question remains, why are all these new components (or verified components) causing the same trouble?

You stated that this is a 3-wire, 1 HP pump and you measure 7 A when it is running. Do you infer that 3 wire means 3-phase? If it is 3-phase, did you measure the current on all three phases? Did you ever have the chance to measure the current on all phases when the pump was supposed to be running but wasn't? This would be critical information for troubleshooting.

If you are losing one phase, this would cause your pump not to run, but you would still read current through one of the other legs. Did you replace all the wiring down the well string to the pump and motor? If the wiring is all still original, it may have been that the old pump "swung" in the casing when cycling on and off and twisted the wiring and now one lead has been damaged and is only intermittently providing continuity of power to the motor.

If you lose a phase on the motor, it won't run but will overheat and go into a thermal overload. You would have to remove power and wait for the temp to come down and retry starting it later. Maybe it would restart or maybe it wouldn't and it would overheat again and you would have to wait once again.

This is the direction I would focus my attention on at this time, at least to rule it out. One wire may not be open circuit at all times, but make poor contact intermittently. That is all it would take to cause this problem. There should have been a torque limiting device down inside the well to prevent the motor from twisting the pipe and wiring. If that failed or was non-existent, this could be a legitimate possibility. I would also check all the wiring connections above ground, too.

RADAR

 

[Reach4]

Actually no. The previous one didn't have one and neither does this I was under the impression that a 3 wire has the start up coil built in

A "3 wire pump" today has 4 wires including a green wire for a ground. When put into an old well that lacks a ground wire only has 3 actual wires run, the green is not used.

A "2-wire pump", which has the start connections internally, today comes with 3 wires including a green wire for a ground. When put into an old well that only has 2 actual wires run, the green is not used.

Do you know the model number of the pump?

 

[ACWxRADR]

At the depth that this pump is set, I certainly hope that it is a 3 phase (3-wire) system. That length of wiring (340 feet) would create too much line loss for a single phase motor. The voltage drop at the motor connection would surely be substantial and the pump would either not operate at all or would overheat in a short time, regardless of the water cooling. This could actually be the source of the problem if so wired.

RADAR

 

[Reach4]

At the depth that this pump is set, I certainly hope that it is a 3 phase (3-wire) system. That length of wiring (340 feet) would create too much line loss for a single phase motor.

Few residences have 3 phase power in the US. For a "3-wire" motor, there is a control box with a starting capacitor to provide the needed phase shift to get the pump started. That capacitor is usually disconnected by a relay in the control box once the pump is going.

That length of wiring is not a problem, although the wire should be selected with the wire length in mind.

This graph is from the Franklin AIM manual for "60 degree C" wire. I think these are round trip distances rather than wire length.

 

[ACWxRADR]

Reach,

I do understand the wiring gage considerations, but don't most newer water well systems convert single phase to 3 phase output within the drive? This point maybe moot, because I don't know everything about Scott's system. He may not have a VFD drive that does this conversion, it may be just a single phase system.

However, single phase or three, with or without a drive, Scott could still have a wiring or electrical connection issue somewhere. If the problem isn't above ground, like a poor terminal connection, it could very well be the wiring down to the pump through the well string. I suspect, just on a hunch, that the wiring down the hole has a bad spot.

It is either this, or the water level in the well is not where Scott believes it to be. But can he be that wrong? Scott sated that the static water level was 150 ft and the pump was at 340 ft. That provides a huge margin for error. Still possible, but in my view, not a probable cause.

I do not believe the problem is with the pump, pressure switch or tank and the setup as the problem existed prior to replacing all these and verifying the rest and the problem still exists, so it is something else. It is something that has still not been addressed or checked. That leaves wiring as the biggest suspect, at this time and without more information.

RADAR

 

[Reach4]

do understand the wiring gage considerations, but don't most newer water well systems convert single phase to 3 phase output within the drive? This point maybe moot, because I don't know everything about Scott's system. He may not have a VFD drive that does this conversion, it may be just a single phase system.

VFD has controller with a lot of electronics. While you would think having electronics would increase reliability, it does not. I don't know what percent of new residential pumps convert to 3-phase, but I expect it is fairly small. It may be like tankless water heaters-- if you judged by the % of posts about failures, you would overestimate the penetration rate.

I was suspecting that Sans1964 had an old controller box with an old start capacitor. That would have explained the intermittent starting symptom.

It will be useful if Sans1964 posts the model of the pump.

 

[ACWxRADR]

VFD has controller with a lot of electronics. While you would think having electronics would increase reliability, it does not. I don't know what percent of new residential pumps convert to 3-phase, but I expect it is fairly small. It may be like tankless water heaters-- if you judged by the % of posts about failures, you would overestimate the penetration rate.

I was suspecting that Sans1964 had an old controller box with an old start capacitor. That would have explained the intermittent starting symptom.

It will be useful if Sans1964 posts the model of the pump.

A START cap would be a very common failure. However, what we need to help Scott out is more detailed information about the whole system. Troubleshooting in this venue is always problematic as there is always one more item that is missing from the equation that needs to be discussed. Like the detective, Lt. Columbo... Just one more question..

RADAR

 

[Craigpump]

No, not all new systems convert single to 3 phase. Some installers, like myself don't promote those systems due to unreliability and the high cost of replacement drives.

I have seen control boxes hidden in floor joists, behind Sheetrock so without a pic of the exact pump prior to installation or pump and motor number we're just speculating

What are the start amps?
Do you have amp draw even when you have no water?
Was the wire down hole replaced?
Was the wire from the controls out to the well ohm'ed out and determined to be in good condition?
If you relieve the system pressure do you then get water?
Is there a galvanized nipple under the pressure switch?

 

[Boycedrilling]

That was one of the things that confused me starting out 30 years ago, in the mid '80's. New 2 wire pumps had 3 wires. 3 wire motors had 4 wires. This is about when the national Electric Code mandated adding a ground wire to submersible wires. For 30 YEARS now a ground wire has been required. If the pump is pulled and reinstalled and it doesn't have a ground wire, one MUST be added. We replaced one just last week that didn't have a ground wire. The ground wire can be connected to one of the mounting studs of the motor.

Large hp Hitachi motors still do not come with a ground wire installed. The installer has to add one.

 

[PumpMd]

http://franklinwater.com/products/drives-protection/residentiallight-commercial/subdrivemonodrive

Monodrive systems, you can use a standard Franklin 3w control box that matches the hp to troubleshoot.

 

[Valveman]

Actually no. The previous one didn't have one and neither does this I was umder the impression that a 3 wire haf yhat yhe start up coil built in

With no control box this is a 2 wire system. The third wire is just a ground. So there is no capacitor to worry about.

No, not all new systems convert single to 3 phase. Some installers, like myself don't promote those systems due to unreliability and the high cost of replacement drives.

I have seen control boxes hidden in floor joists, behind Sheetrock so without a pic of the exact pump prior to installation or pump and motor number we're just speculating

Do you have amp draw even when you have no water?
Is there a galvanized nipple under the pressure switch?

It is possible that you have a hidden control box. Trace the wires and make sure they go directly from the pressure switch down the well to make sure there is no control box and no capacitor to worry about.

Then like Craigpump says. check to see if it is drawing amps when there is no water. 7 amps is correct for a 3/4HP. If it is not pulling any amps, check to see if you have voltage on the 2 wires coming out of the pressure switch to the well. If it is pulling 7 amps and not pumping water, you have a main line break somewhere. If it is pulling low amps like 4, you are pumping the well dry. If it is not drawing any amps and there is voltage out of the pressure switch, the overload in the motor is tripped. If there is no voltage coming out of the pressure switch, the points could be bad or the nipple to the pressure switch clogged.

 

[ACWxRADR]

As I stated, I am no expert nor a professional when it comes to these systems,

However, one of the major root causes for this failure has not yet been ruled out - the wiring en route to the pump motor. Regardless if this turns out to be a 3 phase or single phase system, the wiring down the well string to the motor is still suspect in my book. If the motor was not installed with some torque limiter to prevent it from twisting the wires or if that torque limiter had failed with the old pump, the damage to the original wiring would still be present if it has not been replaced.

Throughout the wiring harness leading down to the motor, there could be many broken strands of conductor wire. If there were enough in one section, total loss of power to the motor might occur intermittently. Or, if the circuit was not totally open, it may be creating a greater voltage drop over the line and present a low voltage condition at the motor, causing it to run at a lower RPM, run hot and go into a thermal overload.

The first rule of troubleshooting any system is to check the power supply, so this is where I am navigating to at this time.
A good clamp-on ammeter with a max-min record feature would help in troubleshooting this system. Then, it would be up to Scott to record some current and voltage data over time - when the pump and well system is operating good as well as when it is not.

RADAR

 

[Valveman]

If there is voltage coming out of the pressure switch but the pump is not drawing any amperage, then it is possible to have a broken wire down the hole. But it would be much more likely that the overload in the motor is tripping, especially if the pump comes back on by itself after a few minutes.

 

[Craigpump]

Is your electric bill abnormally high? If so, I would look for a leak and that would explain why you have water after waiting awhile because the well has had a chance to recover.

 

[Sans1964]

First ler me thank you to all of you. Your willingness to help is awesome. I have some new info. Well I ran into no watet again. Pressure was zero . Turned off the disconnect clamped my amp probe on and threw the swich. Start up about 7 1/2 amps. Run draw about 4 1/2. Amps. Pressure started coming up. Got to 20 or so psi. Then slowly dropped off to almost nothing. All the while the pump was still pulling 4 amps. Im guessing it was and is running. Not stopping as I thought previously. I dont know the model # but will ger it in the morning. Its a 220v 2 legs and a ground. Bith legs are good I checked voltage and current during operation. Suddenly thinking not the pump at all. Foot valve maybe. I really dont know at this point. But my wife is going nuts and is going to kill me. Any ideas are greatly appreciated

Scott

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[Sans1964]

New info!!

I did the on off again start up and run was 7.7 amps per leg! System pressured right up to 62 . So why the 4 1/2 amps and no pressure. ?? I think its time to pull the pump. And re wire it. The pump was replaced 2 weeks ago. But im sure the wire was not. Otiganal install was 2001. The only thing that is left is the wire. Everything else has been replaced

 

[Ballvalve]

New info!!

I did the on off again start up and run was 7.7 amps per leg! System pressured right up to 62 . So why the 4 1/2 amps and no pressure. ?? I think its time to pull the pump. And re wire it. The pump was replaced 2 weeks ago. But im sure the wire was not. Otiganal install was 2001. The only thing that is left is the wire. Everything else has been replaced

Pretty crazy not to change 12 gauge wire. But you have an odd problem. Would seem to say you are pumping the well down. Read valvemans post.