Submersible Pump- Voltage Drop

[Plainview]

I have a 1-1/2 hp submersible pump which stopped working. I have voltage to the pressure switch, but when I engage the switch the voltage drops to zero. I then have no voltage at either the switch or at the pump controller.

There are only 2 wires running into the pressure switch and I read 110V.

What is this symptomatic of? What should my next step in troubleshooting be?

I've read that the first step in most of the troubleshooting is that you should make sure your pump has the proper voltage, which, mine doesn't.

 

[Valveman]

Punch the red buttom on the bottom of the control box.

 

[Sponsor]

 

[Boycedrilling]

I assume that the two wires to your pressure switch are both wire to one side of the switch. A pressure switch has 4 wire connections, not counting grounds. It can make or break the electrical connection to 2 sets of wires.

Some installers only wire one of the two 120 volt legs thru the pressure switch. You're only breaking one leg of the power with the pressure switch. Does this work? Yes. Is this the best way to do it? I don't think so, I wire both legs thru the switch and break both legs.

The only time I run just one pair of wires and use only half of the pressure switch is when the control box has a Contactor. Then the pressure switch is just making and breaking pilot amperage.

 

[Plainview]

Yes, there are 4 wires total. Only 2 supply wires though.

Any idea on the voltage drop?

 

[Plainview]

Valveman,

The pushing a button solution is always the easiest. Unfortunately my control box doesn't have a button on it, in it, or around it (picture attached).

Would that red button have been a reset for the controller? Is there a way to reset the controller without a button?

 

[ThirdGenPump]

Where is your breaker box in relation? Any junctions between the panel and the pressure switch? It sounds like a ghost voltage issue, which is an electrical problem. There is a bad spot somewhere in the circuit. I'd try changing the breaker, running a temp wire between the panel etc.

 

[Boycedrilling]

Couple of month ago I had a 3 hp wired the same as yours. The pressure switch was just breaking one leg, not both. I was reading 120v on line 1 and line 2 with the multimeter. Until I shut the breaker off and tested the incoming lines. There was a fault one just one of the incoming underground lines. The pump or control box was back feeding enough voltage to show voltage on the bad leg. But there were no amps. The pump wouldn't run. Had the electrical company repair the ground fault and the pump ran fine.

I did go back later and change out the control box for one with a Contactor. The original install was direct switching the 3 hp thru the pressure switch. A square D FSG pressure switch is only rated to switch 2 hp maximum.

 

[Boycedrilling]

Can't read a date code on your control box, but I'm going to guess its at least 30 years old. I'd consider replacing it just from the age stand point.

 

[Plainview]

A little bit more information:

The plate on the cover of the pump controller is for a Berkeley 4BM12 pump 1.5hp 230V, single phase.
The plate on the bottom portion of the pump controller is for a Franklin 1.5hp pump dated 1981.
The capacitor appears to be significantly newer than 1981. I think they just used an old controller box.

The well (per state logs) was drilled in 1997. It is 110' deep. It rated 35gpm at the time.

There are only 2 conductors coming up out of the floor to the sub-panel. I measure 110V coming off those before they go into the sub-panel (with the breakers turned off, if that matters). The breaker is two pole, 30A. I think that the conductors coming up out of the floor run directly to a main switch right on the power pole (about 150' away).

Only 2 conductors run into the pump controller (from the pressure switch). There isn't a separate conductor running from the panel straight to the controller.

So, a couple of questions:

1) Can I get 230V off two conductors? How can I check if I should be getting 230V or 110V?
2) Is it possible I actually have a 110v pump that they just used an old controller for?
3) What's next in troubleshooting?

I've called the original driller/pump installer out this week, but I'd like to make sure he's not going to want to replace the pump unnecessarily. I'd also like to understand more about the system myself. We're new to the house (in the last 6 mo) and it's our first well.

 

[TVL]

There are only 2 conductors coming up out of the floor to the sub-panel. I measure 110V coming off those before they go into the sub-panel (with the breakers turned off, if that matters). The breaker is two pole, 30A. I think that the conductors coming up out of the floor run directly to a main switch right on the power pole (about 150' away).

I'll just jump in and make a few observations:

1- You are reading voltage with the breaker OFF ?????? Unless I missed some other information from earlier post, this should not be the case!

2- Are you reading across the two conductors and getting 110 VAC? Or across each conductor to ground?

3- If the breaker to the PUMP is truly OFF and you're getting 110 VAC, then someone has something wired incorrectly and you getting back-feed from another circuit. Truly a guess at this point, but if someone wired a shared circuit in the past (which isn't to code), that is the reason for your reading with the pump breaker OFF.

4- After reading your post again, I'm thinking I'm probably not interpreting the post correctly!

5- Oh by the way, if the two conductors are wired properly to a double breaker, you will most certainly get 240 VAC across them .............. not 120 VAC. So then, are you getting 120 VAC across the two conductors?? Or to ground??

6- And there is no ground wire with the two conductor wiring or is it you simply didn't mention the presence of one??

7- boycedrilling inquired about the wiring on the pressure switch, not the control box. It would be of interest to see a photo of the pressure switch wiring.

 

[Reach4]

5- Oh by the way, if the two conductors are wired properly to a double breaker, you will most certainly get 240 VAC across them .............. not 120 VAC. So then, are you getting 120 VAC across the two conductors??

Continuing in that same topic, the pressure switch should have 4 wires going to it. 2 from the breaker, and 2 to the pump controller.

Measure across each left-half contact to each right-half contact. That is 4 voltage measurements. What is the highest VAC that you read that way?

 

[Plainview]

1) I only measured the voltage going to the sub-panel with the breaker off. It measured the same with the breaker off or on. This is before the power gets to the sub-panel or the pressure switch. All of the other voltage measurements had to be with the breaker on.

2) 110 (114 actuall)V AC is between the two conductors, black & white. I get 120V from black to ground and 2V from white to ground. This is at the wires coming up into the floor, prior to them getting to the breaker box.

3) 110V with the breaker off is only before the breaker. After the breaker I have no voltage with the breaker off. With the breaker on I have 110V at the pressure switch.

4)

5) 110V between the conductors. See 2).

6) All of the wires are 2 conductors plus a ground wire.

7) See the attached picture of the pressure switch. The conduit on the right goes to power. The conduit on the left goes to the pump controller.
I also attached a picture of the breaker box. Pretty simple. This wiring was working (for probably 20 years) until last Thursday.

I measure the following at the pressure switch:
- 110 (actually 112)V between the White and Black wires on the power side.
-119V between White & ground on the power side
-2V between Black and ground on the power side
-0V between the wires on the controller side
-I get 75V which falls quickly to zero between white on the power side and either white or black on the controller side.

 

[Boycedrilling]

Ok you do not have 230 volts to the pump.

There is no official color code for wiring, except for equipment ground, which must be either green or bare copper. In a 120 volt system white is normal,y used for the neutral wire. In a system wired to current codes, the ground and the neutral circuits must be separate all the way back to the main panel, where they are bonded together. A 240 volt circuit does not need a separate neutral wire, the 2nd 130 volt leg acts as the neutral for the 1st, and vice versa.

In your system you have a black wire and a white wire. Both are 120 volt circuits. Both should measure 120 volts from the wire to ground. Then you put one lead of the multimeter on the black wire and the other on the white wire. You meter should now read 240 volts, leg to leg. You probably don't have that. You need 120 volts on each wire to make a 240 volt circuit. Clear as mud?

You are only getting 2 volts on the white wire leg to ground. It is broken or shorted out somewhere.

 

[Plainview]

OK, it must be between the sub-panel & the switch at the meter then. Is there a way to test wire continuity? This whole wire is underground.

 

[Boycedrilling]

ok I just looked at your photo of your sub panel. It is a lugged panel with a single 2 pole breaker for the pump. With the breaker off you measure fron the white lug to ground, then from the black lug to ground. Both of those measurements should be 120 bolts. Then measure from the black lug to the white lug. You should have 240 volts. If you don't have those readings, your problem is back up the line.

Go to the main panel. Take the same reading on the output side of the breaker feeding your pump sub panels itch the breaker on. If your meadurements ar now correct, your electrical problem of s between the main panel and the sub panel. If the measurements are not correct, take measurements at the main disconnect in the main panel.

 

[Boycedrilling]

Yeah it sounds like you have a ground fault. Is the wire yours or the power company's? Is it in conduit or is it direct buried? My dynatel wire locator has a ground fault loop to find the location of a bad wire. You my be able to get your power company to locate the fault for you, other wize you will need an electrician with the specialized locating equipment.

 

[Boycedrilling]

I had a customer that had a ground fault between the power pole with the transformer on it and the meter at the pump house. It is about 150 ft between them. The PUD offered to split the cost of replacing the line with him.

 

[TVL]

You are only getting 2 volts on the white wire leg to ground. It is broken or shorted out somewhere.

Boycedrilling is correct ................ at least I'm betting on it! You have lost voltage to one leg. It simply could be a bad breaker switch, a loose connection, a broken section of wiring, etc.

You mentioned in an earlier post your pump was fed with a two pole 30 Amp breaker. Then that means you should have 230 VAC at the pump. That is what the wiring dictates. So, unless you have other unforeseen problems, you have a power issue and once resolved, the pump should run!

Follow the circuit back and determine where you have the proper 230 VAC. Then move forward to find where it is lost. Between the last known voltage reading and the pump may be a section of underground wire .................. and who knows, this may very well be where the "break" is located. It happens! But, you can find it. Or, simply replace the wiring between the last know section that yielded 230 VAC and the water pump and forget about finding the break. Either method should get you up and running.

You did mention in an earlier post: "I think that the conductors coming up out of the floor run directly to a main switch right on the power pole (about 150' away." I'm not quite following this. Are you indicating you are getting power directly off of a power pole? No power meter? No power panel? I doubt I'm reading this correctly. Anyhow, somewhere back at the pole should be 230 VAC. Or you need to contact an electrician and/or the power company.

 

[Plainview]

Problem solved. See the attached photo.

I tracked the voltage back to the meter and there is a 2nd (very old school) fuse box within the switch. I replaced the burned out fuse and success!!!!

I sincerely appreciate all of you who took the time to respond. It helped me learn a lot more about my system and saved me a costly service call.

Thank you!

 

[Boycedrilling]

It's not rocket science, but it does give you a sense of accomplishment to successfully find the problem doesn't it.