Maybe this is a common thing, but I'd never seen it before;

When under heavy draw (say washer, shower and hose running at the same time, or just refilling the pressure tank after a drain and filter change), my well pump will cycle on and off, independent of the position of the pressure switch (which is very nearly new). It will run for about 15 seconds, stop for about 10, switch back on, etc, until the pressure switch cuts the power.

Well pump is a submersible, no idea the depth or HP, 30 years old.

During these "off" periods (while the Pswitch is still 'on'), if my washer is filling, I'll get almost zero pressure on the second floor of the house.

Thoughts?

 

You say heavy draw but does it happen when you first start using water or does it happen after using a lot of water? How have you determined that the pump is cycling on and off?

The first thing that comes to mind is that the pump is running when you think it's turning off and on but you are actually pumping your well dry. The second possibility is that the thermal overload on the pump motor is kicking in and turning the motor off.

 

Seems to happen after using a lot of water.
I'm drawing the conclusion that the pump is turning on and off because I can stand right at the well entry, which is next to the switch and pressure tank, watch the pressure guage climb, pause... climb... pause, all without the telltale click of the pressure switch opening and closing it's contacts. I can also feel the flow of water by putting my hand on the incoming main pipe.

Would the pump shut itself off internally if it ran dry?

 

I'm betting that you're running out of water and the pump is intermittently sucking air. A bit of water flows into the well and it pumps it up and draws air again which makes you think the pump is turning on and off. I would stagger your water usage or start getting quotes for a new well.

No, the pump will not turn itself off it ran dry at least initially. Being submerged in the water cools the motor. If it's run dry long enough it will overheat and if will turn itself off if it has thermal protection.

If you have an amp meter that clamps around a conductor for the pump you can monitor how much current it's drawing and verify if the motor is actually turning off. The load and current draw will drop when it's sucking air but it will not drop to zero like it would if it shut completely off. You might also go to the well head and feel the pipe right where it emerges to feel the subtle vibration of the motor running. You can also press your skull against the pipe so the sound of the running motor can transmit through to your ear.

 

Hm.... nuts...

Let me ask this, if the pump is drawing air, would I see it come through? I've got a transparent sediment filter and particle filter and never seen any bubbles come through from the well line.

I suspect I'm in for looking at a pro to evaluate the water level and redrill? ... double nuts.

 

You may or may not see air in the filter. The pump isn't designed to pump air so if it can move air up to the filter it is mostly by accident and probably only happens where there is water flowing to carry the air bubbles up to the filter. If the water flow has already stopped the bubbles are probably trapped in the pipe down in the well..

The easy thing to do is stop using a lot of water continuously. Spread out showers, dishes and laundry. If the problem goes away you pretty much know that you are using water faster than the well can provide.

A well sorta has two parts; how fast water enters the well and how much water it can store. Water often enters the well at a slow rate of like a gallon or two a minute. That's less than you use during peak times so the well is drilled deep. That depth allows the well to accumulate or store water to accommodate your surge demands.

Years ago people did not use as much water and with development there are a lot more people pumping water from the underground aquifer so it's level may have dropped over time. So, the well that was good 30 years ago may not be up to today's standards. The problem is that it is not permitted to deepen an existing well so your primary option is a totally new well which can be many thousands. So, it's much less expensive to simply alter your usage patterns to spread out your water usage.

 

First, thanks for all the information Dane, you've been hugely helpful.

Understood on the usage pattern alteration. If that turns out to not be viable, question on the well re/drill;

Is that some sort of code/regulatory issue, or a technical/practical issue? I see you're in NC too, so I assume if it's the former it'll hold true for me as well.

 

The biggie is that code does not permit a well to be deepened. I have never found a valid explanation as to why. My inspectors say it's to prevent contamination but I don't see how it would be any different than drilling the well in the first place.

I would certainly try to spread out you usage and live with your current well. Drilling runs $10-$15 a foot. I have good water from a 190 foot deep well. My neighbor's first two holes were dry down to 500' each before they got water on the third attempt so you really don't know what you'll be getting into.

 

Before jumping into a new well, I just wanted to reiterate what Dane posted above. It is very possible that the pump is failing. My pump failed like that where it would pump for a while and then stop. I put a clamp on amp meter and I could see the amps jump up when it stopped pumping, which means the rotor was locking up.