Troubleshooting my deep well - low GPM / pressure

[NIFARON]

Hello all! Looking for some guidance! Sorry, this is a little long, but I've been chasing this for a bit now -

Summary: Is my GPM extremely low, or is this to be expected?

We bought an acreage with a deep well that had the pump replaced 2 years ago by a local plumbing company. They installed a 3/4 HP Little Giant model W12G07S9-22S - 12 GPM.

My current flow at a hydrant is ~2.5 GPM at very little pressure... sotra just trickles. Never builds up enough pressure to kick the pressure switch off. Just runs until the power is cut at the breaker. It's been this way since we bought the place a year ago.

First I isolated the well head from the pressure switch, tank, hydrants, etc - hooked a hose straight to the well head - still about 2.5 GPM.

So I pulled the pump tonight - photos here: https://www.facebook.com/nifaron/posts/10155760966188814

After pulling the pump up about 10' I tested once again (wondering if it was too low), same GPM.

After pulling it all the way out and laying the pipe across the ground I put it in a stock tank and it will output about 10 GPM pushing thru 160' of 1" line.

The depth of the well overall is 192 ft, the water is 102 ft down from the head, and the pump was hanging about 160 ft from the head.

The pump is 3.9" across, and the well casing ID is just over 4" - is this too small?

Pump is 2 wire 220 VAC - voltage reads fine on both sides of the pressure switch.

Thanks very much!
Aaron

 

[Reach4]

the water is 102 ft down from the head,

If you want good pressure, a 16 GPM 3/4 HP is not appropriate. 10 GPM 3/4 HP would give better pressure.

That said, I think your pump is bad. You should not have gotten low pressure once you put it into ground level water.

The pump is 3.9" across, and the well casing ID is just over 4" - is this too small?

If the casing is PVC, 3.9 is fine. If steel, you want a 3.75 inch pump or smaller, and many would suggest a 2.9 inch pump for 4 inch steel.

 

[Sponsor]

 

[Craigpump]

That casing looks pretty mangled, how are you going to get that sealed so surface water doesn't get it?

Put a gauge on the end of the pipe with the pump in the stock tank, how much pressure will it build?

 

[Valveman]

Looking at the pump curve, if the water level pulls down close to the pump, that model would barely build 50 PSI. Will it shut off if you lower the pressure switch to 30/50?

 

[NIFARON]

Thanks all for the input!

I pressure tested the pump in the stock tank (thus no lift), and only got 60 psi.

Went an purchased a new 1 HP pump, and tried the same test... it was over 180 psi before I chickened and shut it off.

Purchased new line, and power cable... going to go the 100% replacement route.

Any value in trying to the get Little Giant pump repaired / rebuilt to keep as a spare?

Thanks!
Aaron

 

[NIFARON]

That casing looks pretty mangled, how are you going to get that sealed so surface water doesn't get it?

This may not have been the best solution, but the redneck in me thinks it'll work - basically I took a long piece of 6" PVC pipe and encased the OUTSIDE of the well casting down into the clay several inches. Then I used a 4" to 6" PVC bushing that rests on the top of the old well casing and allows me to hold a standard 4" split seal. My casting ID is ~4.75, and I wasn't having any luck finding one that fit.

Photos here - feedback welcome!:
https://www.facebook.com/nifaron/posts/10155766393578814?pnref=story

Thanks!
Aaron

 

[Craigpump]

Nope, it's junk.

I think the most important thing is to figure out why the other pump failed, and keep that from happening to the new pump.

 

[Craigpump]

Ahhhh yeah it may work, maybe not. Certainly not an acceptable repair where I live. I wouldn't want my family drinking it without going thru a UV system.

 

[NIFARON]

Ahhhh yeah it may work, maybe not. Certainly not an acceptable repair where I live. I wouldn't want my family drinking it without going thru a UV system.

In my case we drink rural water, this is only for livestock and washing vehicles due to the presumed farm chemical contamination. As a safeguard I'll make sure the gap between the OD of the casing, and the ID of the 6" PVC is well sealed.

Thanks!
Aaron