Diagnose our electricity/low-flow well/well pump/expansion tank/heater
August 31, 2020 3:58 AM   Subscribe

Our electricity usage sometimes spikes, and we think it's because our well pump and maybe also our water heater gets stuck running. We're not sure whether it does that because our well is low and needs fracking, because our expansion tank is faulty and needs replacement, or something else. Can you help pin it down?

Here's what we know:
We have a very low-flow, very deep well: 1/4 GPM, 540' deep. Before we moved in, when no one was living here and it was a wet time of year, we saw water dripping from the top of the well, suggesting that the water table sits high at least sometimes. But since then, when we've tried to troubleshoot, the water has been so low in the well that we can't be sure we ever hear a dropped ice-cube hit.

Before we even bought this house, we talked with the local legend pump guy (LLPG) (also referenced here), and he said that we should hydrofrack the well. But, aside from the incident referenced in that question, and one other time when I left a hose dripping, we haven't seen water dwindle at the tap. There's just two of us in the household, and the low GPM didn't seem to come into play. So we haven't felt the need to frack.

But, we've been finding that sometimes our electricity usage spikes. We think it's because the well pump, and maybe the water heater in turn, gets stuck running and running. LLPG came by a few weeks ago, and when he pressed the valve at the top of our expansion tank, water came out. He explained that the tank bladder is leaky, and since the tank can't attain pressure, that's why the pump gets stuck on. He used an air compressor on the expansion tank, which he said might make it work for weeks or months, and suggested a new tank soon-ish. (And again refused to accept any payment, so I told him we'd just accidentally bought a package of baby back ribs that I couldn't eat, and he allowed that he could put those to use...)

We've been watching our electricity in the weeks since, and it recently spiked again, after a long shower. That's happened after long showers before. I looked and the pump was stuck on again. I flipped the circuit off, and called LLPG for a new expansion tank. He came by, flipped the circuit back on which immediately brought the tank up to pressure and cycled the pump off. He pressed the valve at the top of the expansion tank, and it did not spray any water. He concluded that the tank wasn't the culprit, that we should frack the well now, and that we will need to replace the tank at some point but not yet. He also said that while the pump might be a couple hundred feet up instead of the ~50' he'd thought before, he doesn't recommend lowering it. Fracking costs thousands but doesn't involve the LLPG; replacing the tank costs hundreds and does.

So: 1/4 GPM, we're in a drought on top of the driest time of year, water so low that we don't hear an ice cube hit water, the problem happens after long showers, LLPG says to frack before bothering with the tank... Sounds like we should frack, right?

Here's why I'm not sure, and could use your input:
- First, even when the pump gets stuck on, we don't have dwindled water at the tap. Unlike the time the water ran out or the time I left the hose dripping, it runs fine. We only know there's a problem when we see our electricity usage spike, and then confirm that the pump is stuck on.
- Second, I'm not understanding what's happening with the water level in the well. The most recent time that the pump got stuck on was in the morning, after the dishwasher ran (~6 gallons, according to the manual) and I took a long shower. If we DO get 1/4 GPM even in a drought at the driest time of the year, we should have had >100 gallons in the well when we woke up, and I can't see that being used up by the dishwasher and shower. (I CAN see the water in the expansion tank being used up, and then some. It's not a big tank.) So how could it be the well's flow that's the problem?
- Third, in addition to high costs, fracking has risks: Our water quality is great and could change. We could end up with overflow, which would be difficult to handle in our location.

I have a well guy coming by tomorrow to discuss the situation and probably to give us a quote for fracking. Anything to ask or to consider? Any forums or boards that would be well-suited for asking this question?
posted by daisyace to Home & Garden (19 answers total) 1 user marked this as a favorite
How do you know your electricity is "spiking?" Are you looking at your electric meter? What does it read? If you turn off the pump circuit, does the electrical spike immediately drop?

Is your water heater electric or gas? If electric, then when you use the dishwasher or take a shower, both the pump and the water heater will turn on at the same time causing power usage to spike.

Have your LLPG guy install a permanent pressure gauge on your water line or expansion tank so that you can tell when your pump should be on or off. So you might have your pump set to turn on at 30 psi and turn off at 50 psi. Then you can compare that to your observations of the pump running.

If the pressure never gets up to 50 psi, then the pump will continue running. It means that the pump is unable to supply enough water. It's running dry.

You may think you have 100 gallons in your well, but you have no way of knowing without knowing the exact depth of the pump and the height of the water above the pump.

The number of gallons stored in your well bore is the height of the water above the pump. For a 6-inch pipe that is about 1 gallon per foot. In a drought, the water table lowers, so, for example, if you have only 10 feet of water above your pump, it only stores about 10 gallons. Even if you wait over night, the water level won't store more than 10 gallons. The well water level won't go higher than the surrounding water table.

I think the best diagnosis will be to install a pressure gauge to see what the actual water pressure is. Your LLPG guy can tell you the turn on and turn off pressure settings for your pump -- for example 30/50. Then observe if the pump maintains the pressure between these two settings. If your pressure never gets up to 50 psi, then your pump won't shut off. It is likely that your pump is at least intermittently sucking air.

And you should never have water come out of the top of the pressure tank. The bladder is leaking. It may be a small leak but it means your pressure tank will not provide the short term reserve capacity that you need.
posted by JackFlash at 9:29 AM on August 31, 2020

How does the tank sense that pressure is high enough to tell the well motor to turn off? If the pump continues to run, then it thinks the tank needs more water. So, two possibilities:
1. the sensor that detects proper pressure in the tank is faulty and is not telling the pump to stop, even when pressure is reached, or 2. pressure is not being reached because the pump is not pumping any water into the tank.

To test for #1, check the tank pressure when the pump is running. If it is at the proper pressure (30-60 psi), then the sensor may be faulty.

To test for #2, disconnect the pipe from the pump to the tank and see if you are really getting 1/4 gpm.
posted by gnossos at 9:36 AM on August 31, 2020

Response by poster: Thanks, that’s helpful so far. Yes JackFlash, we know the electricity is spiking because when our bills went nuts, we started checking the meter once a day or more. Because it’s a digital meter that only ticks once per kWh (except for a little pixel blinking at a pace that’s impossible to determine through the cloudy cover), and because there is some background use of electricity, we can’t tell if flipping the pump circuit off immediately restores the normal usage rate. But as best as we can tell, we think so.

The water heater is hybrid: electric and electric heat pump. We think it might be running too long, and wonder if it would because it’s heating the water that’s there, but the cold water is taking a long time to refill it, so it’s keeps going... But I don’t know if that makes sense with how heaters work.

We do have a pressure gauge, and I think it is a failure to come to pressure that makes the pump keep running, but I’ll take a better look next time. But if so, I’m not sure whether it’s failing to come to pressure because there’s too little water in the well or for another reason. Gnossos, I don’t know how to do test #2. I don’t know where or how to disconnect the pipe, and if I did, I’m still not sure whether getting less than ¼ gpm at that point would be because there’s not ¼ gpm recovering into the well, vs. because the pump isn’t pumping it out as it should.

If it is because we don’t have enough water in the well, then why does it seem like we have enough at the tap?
posted by daisyace at 1:15 PM on August 31, 2020

I wonder if you are confusing water heater power with the well pump power. Your water heater is likely the biggest power hog in your house, much more than the pump. If you run the dishwasher or shower, the water heater is going to run for a while afterward to heat the cold water in the tank back up. Maybe the problem is your water heater and not the pump.

What positive indication do you have that the pump is running? Is there a indicator light or can you hear a sound? And you should really take a look at the water pressure readings to see if they make sense. You should see something like 50 psi when resting. When you open a faucet you should gradually see the pressure decrease to around 30 psi. When it reaches 30 psi the pump should kick on and stay on until it rises to 50 psi and turns off.

I guess the first thing is to figure out for sure whether your power consumption problem is the water heater or the water pump.
posted by JackFlash at 2:02 PM on August 31, 2020

Response by poster: Oh, that’s a thought! I can tell the pump is running because there’s a little box attached to the pressure gauge, with a metal plate that physically closes to turn the pump on and off. It’s where you adjust the on and off psi’s. Though I haven’t changed those settings, I do take the cover off (and don’t touch the live wires!) to see whether the circuit is open or closed. But yes, now that you mention it, differentiating between the water heater’s electrical use and the pump’s is something I can and will try.

Do you know, when I use hot water, does the water level in the water heater drop, and then refill? Or is it typically continuously full?
posted by daisyace at 2:32 PM on August 31, 2020

Response by poster: (Scratch that last question; I looked it up. So, seems like even with our low flow well, the water heater must be staying full continuously or else we'd get water dwindling and/or air sputtering out at the tap, I think.)
posted by daisyace at 2:53 PM on August 31, 2020

The water in the heater continuously refills. The cold water enters at the top of the tank and travels down a long tube to the very bottom of the tank. This is so that the heavier cold water stays at the bottom and the lighter hot water which goes to your faucets leaves from the top. So your water heater is always full of water.

As soon at the thermostat in the water heater detects the cold water entering, it starts up to heat the cold water and will remain on until you turn off the hot water faucet and the cold water that just entered the tank gets to the set temperature. That might take 10 or 20 or 30 minutes after you turn off the tap.
posted by JackFlash at 2:54 PM on August 31, 2020

One thing to note is that your water heater is a hybrid so that it has a combination of a heat pump and also a regular heat coil like an electric oven. If the heat pump portion is not working properly then it will rely more on the heat coil which uses a lot more energy than the heat pump. So you might take a look to see that the hot water heater heat pump is working properly, the air flow is good and the evaporator radiator is clean of dust.
posted by JackFlash at 3:15 PM on August 31, 2020

Response by poster: I’d love to check whether the heat pump is working properly. Any pointers for how? Nothing is obviously wrong to me from looking over the outside of the water heater, listening to it, or using it.
posted by daisyace at 3:30 PM on August 31, 2020

A waterlogged pressure tank (that is, a pressure tank that leaks its pressurized charge of air) will use more and more electricity per gallon of water used. Bear with me on the explanation. It's long and boring.

If you have, say, a 50 gallon pressure tank, when it is empty, it should be entirely full of air at about 35 psi (depending on what your pressure switch is set to cycle at). When the pressure in the tank falls to about 35 psi, your well pump should come on, and pump until it has put enough water in the tank to get to your pressure switch cutoff pressure, often around 55 psi.

That means that your 1/4 gallon per minute well pump should stay on for something like an hour, to get enough water in the tank to compress the air to 55 psi.

If you have almost no air in your tank, then even a little water pumped into the tank will bring it up to pressure, so your well pump cycles on and off, in very short cycles, as you use water. Each time that pump comes on, it uses an enormous burst of power to get started, and if the pump is cycling on and off 25 times when you take a shower, you will notice the increased power usage.

Waterlogged pressure tanks are very, very common, and people who have not become intimate (yet) with their well systems often have this problem after a year or two in the house.

What is the make, and model number of your pressure tank? How tall is it? What is its diameter? What is the part number on your pressure switch, the thing you adjust to change the PSIs?
posted by the Real Dan at 12:09 AM on September 1, 2020 [1 favorite]

Response by poster: That explanation is consistent with my understanding, with one exception. The 1/4 GPM is the refill time for the well. If the well is ok, then the rate into the house is much higher. So the pump should just switch on briefly each time the tank cycles, not stay on for an hour. I'll get you answers to your questions in the next day or two -- I do know the tank is on the small side, and not a brand that the LLPG likes. If we replace it, we'll go larger and with a brand he recommends.

We're going to make some observations of the tank pressure cycles during water use. I have to pay closer attention to what the gauge is doing when the pump seems to get stuck running and running, and also just to the timing of the pressure cycle when the pump seems ok.

Having had the visit this morning from a well guy, we're also going to get in contact with the company that drilled the well for the previous owner, and see if we can learn some things including how deep the pump is. And, we're going to note how long the water heater is staying on, under what conditions, and whether that seems to be what's independently driving the electrical usage.

Depending what we learn, we could hire a pump/well technician to do a service visit, or have someone come assess the water heater, or go back to the idea of replacing the expansion tank first.
posted by daisyace at 11:17 AM on September 1, 2020

If your well guy is there, see if he tell you not just the depth of the well, but also the depth of the pump and the submergence of the pump, that is, the standing water level above the pump. Given the diameter of your well casing, it is then easy to determine how much water storage in gallons you have above the pump. If you are in a drought, the level of water above the pump may be small, meaning you have little storage before running dry.

I agree that observing the pressure carefully over time will tell you a lot. If the pressure is not rising pretty rapidly after a draw down, that would indicate that either the pump is failing or you are sucking air because of the drought. Note that sucking air can overheat and damage a pump because the water surrounding and flowing through the pump cools it.
posted by JackFlash at 12:03 PM on September 1, 2020

Yes, Jackflash is correct: the short-term pumping rate will be much higher than the long-term refill rate, not 1/4 gallon per minute.

I'd fix the tank before fracking: surface equipment should be in good condition before you go underground.

One other complication when the water gets low in a well, especially one as deep as that, is that the pump has to work harder and harder to lift the water above the water surface in the well, and that extra work manifests as a slower delivery rate at the surface. That delivery rate drops to zero once you hit the "maximum head" rating of the pump (some daytons that I am looking at right now have a maximum head of 528 feet).

If your well pump is not fit for your well, then lowering it in the well might result in it not being able to pump at all when the water table got too low.
posted by the Real Dan at 6:14 PM on September 1, 2020

Response by poster: Thank you both so much for all this help. the Real Dan, here's the other info you asked for: the tank is a Flotec FP110T-08. 19 gallons. ("Equivalent to Standard Tank 42 gallons," it says.) I didn't measure it because I figure that was just your workaround for approximating gallons. Label on the pressure switch says Type SK-2, Pentair Water Group.

New info: my husband watched the gauge while I took my shower this morning, and found it IS rapidly cycling. All during the 17-minute shower, it took about 25 seconds to get to the low pressure of 24 each time, and 10-13 seconds to get back up to the high of 45. The flow rate at the shower head varies with that cycle, but I'm sure it's not 19 gallons in 25 seconds! So I think that's conclusive that it's a bad tank (right?). After the tank last cycled off at 45, it continued to drop -- while no one used water -- to 32, and now, a couple of hours later, it's at 48.

During and after that shower, the water heater, which is 60 gallons, stayed on for about 2 hours. I have no idea if that indicates a problem or if that's within the range of normal.

So I think that means that our tank is bad, and that's wasting electricity, BUT WAIT: none of that resulted in the behavior I've seen before, when the electricity usage spiked and the pressure switch got stuck in the closed/on position with no one using water until I flipped the circuit off and manually opened the pressure switch (and maybe the water heater stuck on, too). This shower didn't result in an electricity usage spike and the pump didn't get stuck on. Unfortunately, I didn't know to observe the pressure gauge when it has gotten stuck on. And again, even when that happened, there wasn't any problem at the tap; we only knew we had a problem because of the electricity usage.

So the question now is: in addition to our bad tank, what's the other thing that's responsible for even more of our observed electricity usage spike? But maybe even without knowing that, our course of action should be to go ahead and replace the tank, and see what happens after that?
posted by daisyace at 1:10 PM on September 2, 2020

The rapid cycling is for sure a sign of a bad pressure tank. So first things first. Replace that and see if any of the other problems go away.

The pump stuck on could be one of two things. Either your pressure switch is bad, which doesn't seem likely given your observations that it turns on around 30 and turns off around 50. That's normal.

The other reason for the pump stuck on would be that the well level was low and the pump was sucking air. That could be confirmed if you observe the pump on, but the pressure never rising to 50. The switch won't turn off if the pump can't raise the pressure to the turn off limit, around 50. It will just keep sucking air until you turn off the circuit and allow the well to recharge over night.

It may be rare that the well goes dry, depending on weather conditions and your weekly volume of water use drawing down the water table.

The water heater being on for a couple of hours seems plausible, depending on how much hot water you used. I'm not familiar with how fast a hybrid will reheat. Two hours seems long to me but maybe you could ask a plumber who is more familiar with their operation. Like I said, if the heat pump portion is having a problem, it will fall back to the heating coils which use more electricity.
posted by JackFlash at 2:18 PM on September 2, 2020

Response by poster: Thanks, JackFlash. That all makes sense, but could the pump be sucking air even though we’re not seeing a problem at the tap?
posted by daisyace at 2:51 PM on September 2, 2020

Who knows. The pressure gauge should give you more information. You say the pump is over 500 feet deep. That's a long ways to push up water. The lower the well water level, the higher the pump has to lift. The amount of lift required is from the water level in the well, not the pump level. Maybe when the well level gets low enough the pump can provide 30 psi but struggles to provide 50 psi to the tank so never turns off until the well recharges to a higher level. That could take hours. So the pump isn't running dry, it is just running near the limit of its lift capacity when the water level is low and can't get up to 50 psi.

Intermittent problems are the hardest to diagnose. You just have to wait for the condition to show up again and then gather as much data as you can.
posted by JackFlash at 3:31 PM on September 2, 2020 [1 favorite]

Just for reference, the difference between 30 psi and 50 psi, for example, is about 45 feet of water depth. And for a 6-inch casing diameter, that's around 50 gallons of water which would take around 200 minutes to recharge, assuming 1/4 gallon per minute.
posted by JackFlash at 3:38 PM on September 2, 2020

Response by poster: JackFlash, aha, that could explain it! Thanks again for all your help.
posted by daisyace at 4:31 PM on September 2, 2020

« Older What 2 children's/preteen books am I thinking of?   |   Good middle age group graphic novels for a woke 9... Newer »
This thread is closed to new comments.