Pressure switch fused together

[gsw8doh]

I had a pressure switch fused together at the contact points. The pump seemed to have the proper amps for a 1hp motor. I replaced the switch, and after 8 cycles or so the pressure switch arched and fused back together. My next thought was the pump was bad. We took out 3week old Grunfos 1hp. Replaced with new Grunfos 1hp 10gpm. Replaced pressure switch again, after 10cycles, pressure switch arched again and fused the point together. This is the 3rd pump we replaced, 5th pressure switch. The last pump was sent for testing, nothing wrong with it. What could cause the issue? Brand new pumps and switches using D switches. Is there an electrical issue causing the voltage to drop and spiking the amps? Or is there a voltage leak in the ground causing stray voltage in the well? All wire was replaced, we cannot find a solution.

 

[Reach4]

If you convert the pump from 120 V to 240 V, the switch will be carrying half of the current.

I don't know why the quick failure. It could help if the two poles of the pressure switch were wired in parallel for your above-ground 120 V jet pump (which I presume). But that should only help the switch last more years rather than more hours.

I suggest that you get a clamp around ammeter. They are nice, and could be useful for diagnosing this.

 

[Sponsor]

 

[LLigetfa]

Is the pump in the well? Is there more than one checkvalve? Mutiple checkvalves can create a waterhammer situation that bounces the switch. Where is the pressure switch in relation to the tank? It could be that the switch is too far from the tank and so bounces when the pressure wave hits it. Did you check the small line to the switch is not partially clogged?

 

[TVL]

1- First, I would read over the information at the following site. Hopefully, it may be of some help:
http://www.ecmweb.com/ops-amp-maintenance/basics-electrical-overheating

2- There is no mention of a control box. Therefore, I'm assuming this pump does not utilize one.

3- I would check current draw and verify all is within specification.

2- If you have access to an electrical megger, I would strongly suggest you utilize it to check the integrity of the wiring's insulation. Should this test fail, then that would indicate a breakdown in the wirings insulation, bad splice, etc. I understand that you did replace the wire, but a megger will verify ALL is well.

I would utilize the megger to check circuit integrity from the pressure switch to the pump first. If this test fails, I would then meg from the breaker box to the pump ................ especially if underground wire is being utilized.

 

[Texas Wellman]

110v pump or 220? Did you check your voltage at the switch?

Sum ting wong

 

[LLigetfa]

insensitive post removed.

 

[gsw8doh]

1- First, I would read over the information at the following site. Hopefully, it may be of some help:
http://www.ecmweb.com/ops-amp-maintenance/basics-electrical-overheating

2- There is no mention of a control box. Therefore, I'm assuming this pump does not utilize one.

3- I would check current draw and verify all is within specification.

2- If you have access to an electrical megger, I would strongly suggest you utilize it to check the integrity of the wiring's insulation. Should this test fail, then that would indicate a breakdown in the wirings insulation, bad splice, etc. I understand that you did replace the wire, but a megger will verify ALL is well.

I would utilize the megger to check circuit integrity from the pressure switch to the pump first. If this test fails, I would then meg from the breaker box to the pump ................ especially if underground wire is being utilized.

The engineer from Grunfos asked if I had one too. The wire is only a few months old, it is a new house. The pump is a submersible, runs on 220v, pulling 10amps. It was pulling 10amps when the switch arched and fused. We use watertight heat shrinks that melt and seal in the well, and I did a continuity check on all the wire that is ours. The electrician is saying it is not on his side, and the power company says it is not their fault, but no one can explain why there is voltage on the ground in the main electrical box. I was out there again today, they have also had issues with the electric hot water tank, so I am sure it is something electrical, but since our pump is having an issue it is our fault. Brand new pump, brand new wire, brand new switch, but according to the electrician, something is wrong with our equipment. We requested the power company put a box on and record the power for a week and see if anything shows up. What a nightmare. We did see the voltage drop today from 243v to 207v for about 2sec. I think this is part of the problem as when the voltage drips, the amps will rise.

 

[Reach4]

The engineer from Grunfos asked if I had one too. The wire is only a few months old, it is a new house. The pump is a submersible, runs on 220v, pulling 10amps.

That would be normal for a 1 HP pump.

The electrician is saying it is not on his side, and the power company says it is not their fault, but no one can explain why there is voltage on the ground in the main electrical box.

Say what?!!! Explain, please. Voltage from where to where?

It is hard to imagine a fault where the pressure switch contacts fuse and the breaker does not trip.

 

[gsw8doh]

That would be normal for a 1 HP pump.


Say what?!!! Explain, please. Voltage from where to where?

It is hard to imagine a fault where the pressure switch contacts fuse and the breaker does not trip.

If I put a lead on ground in the box, and a lead to a open breaker I get 2-5volts on a dead line. Showed the electrician and he said that is normal? I am not an electrician and have no idea if this is normal or not, but I would not expect voltage on a ground. As you can see I am dealing with something out of my expertise, but in 10 years I have never had a pump act like that or do anything like this. I was hoping someone has had a similar issue, but I guess not. We may have to borrow a megger just to verify nothing is wrong with the pump electrical, and go from there. Like I said though we replaced everything just to rule out any problems. Lucky for the homeowner it is under warranty.

 

[Reach4]

If I put a lead on ground in the box, and a lead to a open breaker I get 2-5volts on a dead line.

OK. I would not be concerned by that. We could get into it more, but nothing to be alarmed with there. Two people can each hold a meter probe and get readings higher than that.

If you put a lead on a neutral wire and a lead on a protective ground (green), then that would bother me. If you put a lead on a metal water pipe that goes to the earth and a lead on either "ground" or neutral and got 4 volts, that would bother me.

but according to the electrician, something is wrong with our equipment.

What possibly does he think could be wrong with your equipment that would not pop the 25 amp breaker yet would fuse pressure switch contacts together?

 

[gsw8doh]

OK. I would not be concerned by that. We could get into it more, but nothing to be alarmed with there. Two people can each hold a meter probe and get readings higher than that.

If you put a lead on a neutral wire and a lead on a protective ground (green), then that would bother me. If you put a lead on a metal water pipe that goes to the earth and a lead on either "ground" or neutral and got 4 volts, that would bother me.


What possibly does he think could be wrong with your equipment that would not pop the 25 amp breaker yet would fuse pressure switch contacts together?

I really do not know. This has been one of the more challenging calls I have had. I am hoping the electric company finds something on there test. The only other thing I would suspect is phantom power coming from something, or maybe someone drawling high voltage up the line causing a drop at the end. Like I said I am no expert when it comes to electricity. This is the 3rd pump replaced, and the last one one tested and passed with no defects. New pump, still having the same problems. All my tests show our side is working as it should, proper amps but the voltage is inconsistent. I am fighting over who's fault it is and 2 against one does not help. Even the homeowner does not understand how fluctuating power is our fault. Oh well, it is the weekend and I am going to forget about it. Thanks for the help, I will let you know if we get an answer.

 

[Texas Wellman]

Check the voltage across the contacts when the pump is running. It should be close to zero.

 

[LLigetfa]

I am very suspicious that there is some sort of pressure wave that slightly lifts the contacts. Watch the arm that moves the contacts throughout the pump cycle to see if there is movement that could cause the contacts to bounce. The contacts float on the arm with little springs so if you see the gap at the springs changing. The arm could open the contacts just enough to arc, just like a welding rod is held close enough to arc. You may need to record it with a camera and play it back at slow speed.

 

[TVL]

I was out there again today, they have also had issues with the electric hot water tank

Would you happen to know what type issue they encountered with the water heater? Additional information may prove to be very useful! Also, can you find out if any other type electrical issues are occurring around the new home ........... anything the owners might have experienced that seems unusual. I've got an idea or two, but would like additional information first, if at all possible.

In any case, I do hope you will share the outcome with everyone when this is finally resolved!

 

[LLigetfa]

I am very curious what electrical issues could manifest on an electric water heater that would also affect the pump and yet not throw the breaker, assuming the breaker is sized right. An electric water heater is about as dumb as it gets, just a basic resistance element that would have lower current with voltage drop. Also being 240V, there is no reliance on the neutral in relation to ground. Power factor has little effect on a resistance load.

 

[TVL]

I am very curious what electrical issues could manifest on an electric water heater that would also affect the pump and yet not throw the breaker, assuming the breaker is sized right. An electric water heater is about as dumb as it gets, just a basic resistance element that would have lower current with voltage drop. Also being 240V, there is no reliance on the neutral in relation to ground. Power factor has little effect on a resistance load.

Thanks LLigetfa for your insight ............... and trying to keep me on track!

1- First, I simply have to believe there is more to this unusual occurrence than meets the eye, which is partly our problem in trying to help since we haven't seen anything ourselves and only know a few facts.

2- I too am curious if the breaker is sized correctly, but I'm assuming it is .............. and I know we shouldn't assume!

3- To me it makes sense to learn IF there are "other" type electrical issues occurring around the home. Since the water heater was mentioned, I sorta assumed that maybe the occupants were complaining of not enough hot water or it taking too long to recover. A low voltage situation would certainly affect the performance of the resistive load in the heater. However, a low voltage situation should also manifest itself in other ways throughout the house.

4- Since I am assuming a LOT (and trying to think outside of the box), I really did not want to say much until more information could be obtained AND I may be so far off base, that my thinking is purely ridiculous. However, since this is a new home and appears it was just recently occupied, maybe there is a voltage issue to be reckoned with - the OP did state the voltage dropped from 243v to 207v for about 2 sec while they were taking readings. I realize this is a long shot and the circumstances would have to be just right to create the issue he has experienced, but ................

5- For me, it is very difficult to troubleshoot something without being there myself, but I really would like to help if at all possible and I'm obviously guessing or speculating at the moment. I would still very much like to see an insulation tester utilized to verify the pump circuitry integrity and of course there are other things that need to be checked/verified to get to the bottom of this issue. However, since there was a significant voltage drop seen by the technician, I tend to believe that may very well point to something of concern.