Well pump output fade

[Zeeman]

I have a 30 ft deep well with 1.5HP, 4 zones, about 15 years old
I have 6 well points, all same depth, about 30ft each, all connected to the same input pipe, level about 2ft underground, sandy soil. The 6 points are in a straight line about 9 ft apart each.
Here is my problem.
When the pump first comes on, the water production is maximum, in any zone, INSTANTLY, 100% satisfactory.
But after about 5 to 10 minutes the water out put decays slowly to about 50/70% of max.
After about 20 minutes its down to 20/30%
Give it a rest, say 1+hours, and restart the pump, out it comes, INSTANTLY, at max out put.
Then decay starts again.
NO sputtering at the output like it is drawing air, just reduces in output pressure (like an older man at a urinal)
Each zone behaves the same.
Doing this for many years
Can't work out why???
My solution is to run the well pump midnight to dawn, 10 minutes a zone with a 1 hour delay each zone, 7 days
PLEASE any and all comments, suggestions welcome
Thank you
Zeeman

 

[Zeeman]

Adding pictures to explain/support my description.

When I open tap A to add the county water supply with the pump on, the pump output immediately goes to max.
When I close A off, it does not decay instantly but takes quite a few seconds to taper off.

1. Number 1 to 6 are the point locations relative to the pump

2. Letter A on the picture of the pump is the supplementary county water input.

2. Letter B is the ground water input pipe

 

[Sponsor]

 

[WorthFlorida]

I live in zip code 32828. Does this happen during our rainy season? Lately we're short on rain fall. Are you saying you have six points rammed into the ground? No casing?

You're drawling more water than the well can provide and as you stated about an hour+ to recover. With your well setup makes all that water hard to push through the sand.

Using points doesn't take advantage of hydro static pressure from below. A well with a 4" or 6" casing, say 40'-80' deep, water would rise to a level up to 5' below grade. Then with one 2" pipe, 20', inside the casing you draw water.

Local well guys would know best as where your water table is.

 

[Zeeman]

I live in zip code 32828. Does this happen during our rainy season? Lately we're short on rain fall. Are you saying you have six points rammed into the ground? No casing?

You're drawling more water than the well can provide and as you stated about an hour+ to recover. With your well setup makes all that water hard to push through the sand.

Using points doesn't take advantage of hydro static pressure from below. A well with a 4" or 6" casing, say 40'-80' deep, water would rise to a level up to 5' below grade. Then with one 2" pipe, 20', inside the casing you draw water.

Local well guys would know best as where your water table is.

 

[Zeeman]

6 Pipes each ~30 feet down, see attached pic for point spread. No casings.

The thing is, the sprinklers ALWAYS start full bore. This means there is ample water at the start atthe one way valve, 2 feet from the pump

Adding pictures to explain/support my description.

When I open tap A to add the county water supply with the pump on, the pump output immediately goes to max.
When I close A off, it does not decay instantly but takes quite a few seconds to taper off.

1. Number 1 to 6 are the point locations relative to the pump

2. Letter A on the picture of the pump is the supplementary county water input.

2. Letter B is the ground water input pipe

 

[Valveman]

I am guessing you have a suction leak from all the JB weld around the faucet an union. That is not a good way to fix a suction leak.

 

[Zeeman]

Checked that, not the problem

 

[Valveman]

Hard thing to check, How did you do it?

 

[Zeeman]

Hard thing to check, How did you do it?

Thick application of shaving cream

 

[Reach4]

Consider using lower-output emitters to draw the water more slowly.

 

[Zeeman]

Consider using lower-output emitters to draw the water more slowly.

Okay, I do that and all that does is take longer to distribute the same amount of water.
What I seek is an explanation as to why the water delivery drops off that.
My neighbours, left, right and across the street don't lose any pressure during their use.
It's a frustrating puzzle.

 

[Reach4]

I suspect the water level in the points drops. That can be because the screens are crudded up. But it could be something else that causes your pipes to replenish more slowly than the neighbors.

 

[WorthFlorida]

Why are the seven elbows on the intake to the pump?

 

[Zeeman]

Why are the seven elbows on the intake to the pump?

Why are the seven elbows on the intake to the pump?

No reason, just the way I made the connection using what I had available

 

[Zeeman]

I suspect the water level in the points drops. That can be because the screens are crudded up. But it could be something else that causes your pipes to replenish more slowly than the neighbors.

Crudded up points wouldn't cause the water level to drop, would they? As there is no air being blown out means there is water covering the points down there.
Could the pump need some overhaul? Something may cause the pump to lose efficiency after it pumps for a few minutes?

 

[Reach4]

You make a good point. I was picturing the pipes themselves holding water. Are you sucking on the pipes themselves or are you putting a tube into the driven pipe to draw the water out?

As the water level outside the sand point screens drops, there is more suction required. Add that to a possible partial clogging of the screens, and you get a combination that makes it harder to pump the water.
So what we are left with is that the aquifer in the vicinity of the points is being drawn down. Why you, and not your neighbors? Your water goes through a less porous path? You draw more GPM?

 

[WorthFlorida]

The pump does look well dated. Impellers do wear down and as mentioned more suction may be needed. Could be a factor.

 

[Zeeman]

The pump does look well dated. Impellers do wear down and as mentioned more suction may be needed. Could be a factor.

Pump is 13 years old but how/why/what causes pumping degradation from full on to 50% on a regular basis every time restarts. And then stays at 50% after 5/7 minutes of a slow decline?
Puzzle!

 

[Reach4]

The pump does look well dated. Impellers do wear down and as mentioned more suction may be needed. Could be a factor.

The fall-off does not sound like a pump symptom to me.

 

[WorthFlorida]

Pump is 13 years old but how/why/what causes pumping degradation from full on to 50% on a regular basis every time restarts. And then stays at 50% after 5/7 minutes of a slow decline?
Puzzle!

the impeller is threaded on to the motor shaft. After thousands of cycles the threads could be warn down. Threads do always stay tight. As the motor shaft get hot the impeller threads cold be expanding causing slippage.

The impellers are like a disk with the blades inside if it. Usually plastic. When pumping you do pick up sand and millions of gallons going through wear them down. As stated before, more suction is needed and it cannot perform.