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af4ex

New Member

Posts: 11

Location: Florida

1

Tuesday, May 5th 2015, 8:20am

Low Pressure: Is it the pump, shallow well, or something else?

We bought a house in Florida with 1/3 acre and non-functioning 5-zone irrigation system last year. The previous owner installed a new cast-iron 1HP StaRite pump to try to fix the problem, but it didn't help. I found some cracked pipes, repaired them and then everything worked great. Problem solved, I thought.

But a few months ago I noticed that some zones were being skipped. To troubleshoot, I installed a pressure gauge and measured the flow: 30 psi and 8 gpm. Don't know what it was before, but I'm guessing 40psi and 10-15 gpm.

Checked and rechecked everything, but couldn't find anything wrong, but was starting to suspect the shallow well and/or the pump/motor.

Then last week the sprinklers suddenly stopped working, pressure was at zero. I found a crack in the sediment filter holder and figured that was the culprit. But replacing that didn't restore any pressure.

Here's a picture of the system (just after replacing the filter holder). In last photo, I opened the spigot on pump while it was running, producing a steady but very paltry stream which I can easily close with light thumb pressure.


So I'm getting a steady stream, more like a big trickle, from the well, but probably 1-2 psi. Doesn't even move the needle on the gauge. The prime is good and holds steady for days after the pump is turned off.

I suspect it's either the pump or a stuck check valve. But the pump is only a year old and the above-ground Flowmatic brass check valve has no ports for inspection (see photo#1 above). Could it be the check valve at the foot of the well (if there is one)?

I talked to some well-drillers, and wanted them to look at it. But in so many words they said shallow wells like that can't be repaired. They recommended capping it and digging a deep well to replace it ($$$). But my research on the web reveals that shallow well pipes can be readily extracted and repaired, which would be a lot cheaper.

How do I troubleshoot from here?

This post has been edited 2 times, last edit by "af4ex" (May 5th 2015, 2:17pm)


Wet_Boots

Supreme Member

Posts: 5,198

Location: Metro NYC

2

Tuesday, May 5th 2015, 9:17am

Your well point might be clogged. They can sometimes be cleared by back-flushing them.

af4ex

New Member

Posts: 11

Location: Florida

3

Tuesday, May 5th 2015, 9:54am

@WET_BOOTS
>> ...sometimes be cleared by back-flushing...

Thanks for you rapid response. :)

Is back-flushing possibly a DIY task?

How can I test the brass check valve? Is there a simple way to verify the motor/pump is working OK?

Wet_Boots

Supreme Member

Posts: 5,198

Location: Metro NYC

4

Tuesday, May 5th 2015, 11:12am

If you want to get technical with a pump, you could get yourself a vacuum gauge and learn its use. For the purposes of backflushing a point, your pump plumbing must have a connection, either a pipe plug or a boiler drain, upstream of the check valve, so you can force water back down the point.

af4ex

New Member

Posts: 11

Location: Florida

5

Tuesday, May 5th 2015, 2:00pm

Thanks for the info and recommendations. I think my next step is to try to remove the check valve, which will allow me to inspect its condition and also to allow me "upstream" access to the well point pipe. The company who drilled the well (in 2005 and then went out of business) screwed the check valve directly on top the of metal well casing, which sticks out about 2feet above ground. So there is no PVC in front of the valve to splice, as you can see in this picture:

So, my plan (blue text) is to cut the PVC at the red line and use the PVC attached to the check valve as a handle (rotating CCW) to unscrew the check valve.

The check valve is a very corroded unleaded bronze "Flowmatic Enviro-Check M3" (according to the label on it).

I'm a noobie at well digging and maintenance, so am wondering if this is a sensible thing to do. What will happen if I rotate CCW? Will it merely unscrew the valve from the casing? Or is it attached to the well pipe and cause that to rotate too? Will it damage anything? Could it loosen the inner pipe and cause it to drop down into the abyss?

Any suggestions would be appreciated (including 'call a pro!'). :D

Thanks

This post has been edited 1 times, last edit by "af4ex" (May 5th 2015, 2:05pm)


af4ex

New Member

Posts: 11

Location: Florida

6

Tuesday, May 5th 2015, 3:44pm

Also just learned that here in Florida you can call your county water authority clerk and get a "well completion" report on your well (assuming a licensed contractor pulled the proper permits etc). So now I know my well was dug in 2007 and is 74 feet deep. So that suggests it will be much more difficult to work on. (I was assuming it would be 20-25 ft deep).

So I may have to pay a contractor $250 to back-wash it. But he said back-washing only works on about half the clogged wells he encounters. I just want to be sure I've eliminated all other possibilities before shelling out the bucks.

Wet_Boots

Supreme Member

Posts: 5,198

Location: Metro NYC

7

Tuesday, May 5th 2015, 4:47pm

It is very rare to have a well point be set 74 feet deep, because a shallow-well pump can't lift water any more than 25 feet on average. (32 feet is the absolute maximum possible lift, based upon the physical properties of water at sea level altitude)

If your well is a larger-diameter casing, with a drop pipe, then you don't have well-point issues, but you might have a lowered water table to deal with.

af4ex

New Member

Posts: 11

Location: Florida

8

Wednesday, May 6th 2015, 8:10am

>> ... very rare to have a well point be set 74 feet deep,...

Yes, I'm wondering why a licensed contractor would dig a well this deep, knowing that the suction generated by the pump cannot lift water higher than 25 feet or so, the limit established by atmospheric pressure and pump efficiency.

As you can see in the photos above, this is a 'single drop' system. A deep well requires a second drop. But this system has obviously worked (more or less) for 8 years. How is that possible? Unless the screen is somehow positioned at 25 feet or higher. Or, equivalently, is it possible that the instrinsic 'Artesian' pressure could push the water up to the shallow level, and allow a single drop pump to work?

Here is the well-completion report. Can anyone tell me what the "Static Water Level" means? It shows "21". Does that mean the water table is 21 feet below the surface? If so, I guess there very well could be a water table issue here because that level can fluctuate below 25 in times of drought and cause a shallow well to 'dry up'.

af4ex

New Member

Posts: 11

Location: Florida

9

Wednesday, May 6th 2015, 8:33am

Another puzzle here is that there is a large retention pond, several hundred feet in diameter across the street from our house. The level of the pond appears to be just a few feet lower than our lot.

Normally, the pond should 'guarantee' the water table to be at the level as the pond, more or less depending on the demand. But complicating this equation is the presence of a city water pump station about 200 feet away. which operates intermittently. The neighbors think this station is sucking up all of our water and lowering the water table. I'm inclined to agree.

But if the city is siphoning our water, then why doesn't the pond level go down too? It has appeared to be rather steady for the past year.

Very puzzling problem.

af4ex

New Member

Posts: 11

Location: Florida

10

Wednesday, May 6th 2015, 8:52am

I'm wracking my brain trying to figure out how to fix my system, while minimizing the drain on my wallet. So here's a "what if" question I'm hoping someone can answer.

What if I determine that the well system is OK but the water table has dropped below 25 feet. Would it be possible to extract the single drop pipe and just replace it with a double drop pipe with a jet at 70 feet? We know the well is 74 feet deep, so it seems that just swapping out drop pipes could save me a ton of money.

Otherwise I'm looking at about $4000 to abandon this well and dig a new deep well at 200 feet or so.

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