40/60 recovery time

[Morrelli]

Hi, I've got a 550' deep well that produces 7.5 gpm consistently. What I notice recently is the recovery on a 40/60 when pressure switch hits 40, pump turns on, i turn off usage and it reaches 50 in one minute and then it takes 5.5 minutes to cut out at 60. Is this normal? It's like the pump is starving at increased pressure or something. Thanknyou for any reply.

 

[LLigetfa]

it reaches 50 in one minute and then it takes 5.5 minutes to cut out at 60. Is this normal?

No, it is not normal. Sounds like either the pump is way off its curve and on the verge of dead-heading or there is a leak.

Is there more than one check valve between the pump and the tank that could be masking a leak?

 

[Sponsor]

 

[Morrelli]

No, it is not normal. Sounds like either the pump is way off its curve and on the verge of dead-heading or there is a leak.

Is there more than one check valve between the pump and the tank that could be masking a leak?

I don't see a check valve anywhere near the pressure tank setup and incoming pipe from.well head. At the well head things are wrapped up tight, I can remove insulation to confirm.

 

[LLigetfa]

On some very deep wells, some pump installers that did not know the evils of multiple check valves thinking if one is good more are better, would install one at about every 100 feet or so. Multiple check valves can create water hammer that can rupture the pipe causing them to leak. A small leak that is much less than the GPM of the pump can go unnoticed. As the GPM falls off the curve, the amount leaking gets closer to the GPM the pump can produce eventually getting to the point the pump cannot reach the cut-off pressure.

There is no easy way to confirm or rule out if multiple check valves are manifesting this or if the pump is truly nearing dead-head pressure.

 

[LLigetfa]

If you have documentation for the well, sometimes the installer will specify if additional check valves were installed. Even without that detail, if the pump and motor specs are known, taking resistance and amperage readings might provide clues to what is happening. A leak will draw more amps while nearing dead-head pressure will drop amps.

 

[Morrelli]

I can clamp onto pump leads and see if I can gather some info. Last I checked I was drawing equal current on each leg of about 8 or 9 amps, (can't recall exactly). I'll check while pulling first 10 psi then again a few times while pulling between 50 and 60 psi and see what it looks like. Have any of you experienced intermittent check valve operation? I've noticed this occurs more after pump has been running for extended periods during irrigation when cycling is more prevalent, exercising any check valves. In the past the well has had no issue keeping up with irrigation. I put a delay in between zones to allow recovery. Note- any testing I have done includes shutting off main to irrigation and now will.include shutting off main to house just to elimainate any pptential leaks on either.

 

[LLigetfa]

I've noticed this occurs more after pump has been running for extended periods during irrigation

That suggests the water level is dropping and nearing dead-head.

 

[Reach4]

Your water table may have dropped.

I think you should turn the pressure switch down to 35/55 psi. That would be about 1-3/4 turns CCW of the nut on the big spring. Also adjust the pressure tank air precharge down.

 

[LLigetfa]

Your water table may have dropped.

None the less, a pump should not be sized and set so deep that it can dead-head.

 

[Morrelli]

Lots of variables. I isolated main and irrigation. Drained off to cut in. Clamped on, pulling 9.6 A on each leg. Rose to cut out in just over 2 minutes. Did the same with main and irrigation open and had same result. I don't want to agree, but sure sounds like I depleted water level. Thanks for the help.

 

[Morrelli]

Your water table may have dropped.

I think you should turn the pressure switch down to 35/55 psi. That would be about 1-3/4 turns CCW of the nut on the big spring. Also adjust the pressure tank air precharge down.

Reach4, would reducing down to 35/55 be in an effort to reduce the pull on my water table? Is this an effort to conserve pump time as well? Just trying to understand how that may help. I was thinking I would break up my irrigation zones into "manageable pieces" as well, ie., split the number of zones in half and alternate days of watering....thoughts?

 

[LLigetfa]

Reach4, would reducing down to 35/55 be in an effort to reduce the pull on my water table?

It would not affect the volume drawn but it would move the curve to a safer point to avoid dead-heading.

 

[Morrelli]

It would not affect the volume drawn but it would move the curve to a safer point to avoid dead-heading.

Thank you!

 

[Valveman]

If it took 5.5 minutes to reach 60 PSI after a long irrigation zone, I agree you pumped the well down. After the well recovers it fills to 60 in less than 2 minutes confirms this. Spreading out the irrigation zones to allow the well to recover is probably a good idea. Adding a Cycle Sensor to protect the pump in case it can't reach 60 for some reason would also be a good idea.