Pressure drops when pump off

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Old 01-25-16, 10:37 PM
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Pressure drops when pump off

I've got a 210' well with a 3/4HP Utilitech (Lowes) submersible pump running on 240v. The pump was installed 2 years ago. I'm not sure of the tank size right off, but it has a bladder and is holding 25 PSI and I've never added air to it. The well (and everything else) is about 12 years old.

Currently, the pump cannot reach maximum pressure (60 PSI), so it apparently never turns off. The points stay closed on the Square D pressure switch. When I hold the points open or turn the breaker off, pressure drops rapidly and will go to zero if off for more than a few seconds. I replaced the switch while examining for clogging. There was some sediment build up, but replacing the switch did nothing to alter the behavior.

It is my theory that the check valve is not closing. It could be that there is a crack or hole in the pipe, but I can't here anything at the well. When we replaced the pump a couple of years back, the water level was about 15 feet down from the cap (so there's quite a bit of water above the pump), so that may be why I wouldn't be able to hear much at the well.

Two questions:

1) Can anyone offer confirmation or alternative suggestions to the Check Valve theory?

2) If it is a bad check valve, could I simply install a check valve above ground in a convenient location - like under the nice, warm house prior to the pressure switch and tank assembly?

Thanks!
 
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Old 01-26-16, 03:47 AM
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Welcome to the forums! Installing a check valve above ground won't stop the water from vacating the pump and pipe below it. I doubt there will be a shortcut to this. Pulling the pipe and pump to see what has actually gone wrong is the best thing. Otherwise, you will burn the pump up by not allowing it to cycle properly.
 
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Old 01-26-16, 08:47 AM
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I was afraid of that. Is it possible for the pump to last until the weekend when I have the time to pull it? I turned everything off last night. I've turned it on temporarily this morning so we can have some water.

Are there any other likely possibilities?

The pipe is not compromised coming in the house as far as I can see and there's no visible signs between the house and well (about 30 feet or so).

Additionally, it occurred to me that a couple of months back I noticed low pressure at the kitchen faucet, but didn't do any further investigation because I was on the run and the next day everything seemed normal. I was hoping this may be a similarly temporary event...

If the check valve is being blocked by sediment or something, will cycling the pump be likely to dislodge it? Doesn't seem the check valve should be going on a 2 yr old pump, but if the previous event was related, that would lead away from the theory of a leak in the pipe.

Thanks so much for the help.
 
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Old 01-26-16, 09:15 AM
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The check valve will only close when the pump stops running so if the pump doesn't shut off..... it's not a check valve issue. If it was the check valve.... the system would come up to pressure.... the pump would shut off and then the pressure would go down.

It appears that you have a break in the pipe. I can't think of anything else.

I might consider a pump issue and try lowering the pump turn off pressure to 50 psi to see if the pump can make that pressure.
 
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Old 01-26-16, 10:02 AM
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Would your theory be that because the pump can't reach shut-off pressure that it must be a break in the line?

When I manually either shut the breaker off or push the points apart in the pressure switch, the pressure drops to zero rapidly - within seconds. I suppose that could be due to either a break or bad check valve. If manually activating the points on the pressure switch causes pressure to drop rapidly, I would assume the same thing would happen once it hit a lowered shut-off pressure .

While the pump is on, it will slowly build up to about 40psi - around 50 is the highest I've seen. I assume this would point toward a break in the line.

The pump will maintain 30-40psi while running a single faucet and I've checked to make sure it's getting 220v (it is at the pressure switch, anyway).

We've had some cold weather, but we're in North Carolina, I don't think it would have frozen the pipe underground. I don't have a tap at the well head. Is there another way to test where a break might be?
 
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Old 01-26-16, 10:08 AM
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pressure drops to zero rapidly - within seconds. I suppose that could be due to either a break or bad check valve.
That is correct.

There isn't an easy way of checking for a break that I know of.
I would agree that it would not be a frozen/cracked pipe.
 
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Old 02-24-16, 07:26 PM
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I was idly thinking that if you had a check valve before T, you'd know which side the leak was on...that is, either down the hole or the line going to house.
 
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Old 02-24-16, 09:50 PM
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Usually if the break is between the well head and the house you get water coming from the ground or saturated ground.

You could break the line between the house and the well and try pressurizing it to see if the leak is there. You'd need and air compressor as the well wouldn't be connected.
 
 

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