Well pump pressure experiment

Sinks, showers, pipes - usually pertaining to water or sewage. So don't mix them up.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Well pump pressure experiment

Post by kevm14 »

https://youtu.be/KCI6Nt4Ayag

Bill was showing me how his well pump short cycles, which is bad.

What I did was run my kitchen sink into a 1 gallon container and time it. Turns out it flows at almost exactly 1 GPM (I'd rather 2.5 or so but it saves water I guess).

Then I went into the basement and made a video of the pressure gauge dropping until the pump kicked on, raised pressure and finally shut off.

The results are:
- Took about 5-1/2 minutes to drop from about 50 psi to 40 psi where the pump turned on
- 90 seconds later, pressure rose back to 60 psi when the pump shut off

Since I caught it mid cycle (about halfway), I'd estimate it would take 11 minutes to go from 60 psi to 40 psi with the sink running. Then the 90 seconds to recharge to 60 psi is still the same. That means every 12.5 minutes my pump turns on and runs for 90 seconds with a 1 GPM flow. Bill's pump seemed to turn on every 15 seconds and run for like 5 seconds or something, which seems way, way too often. Likely the pressure tank bladder air pressure is low. Or zero. Or the pump is vastly oversized compared to the tank. Either way, a good fix would either be to inflate the tank to the proper pressure, or replace it with a larger one like I have.
This well was drilled about 3 years ago and I upgraded to a double size pressure tank. This really helps extend pump life because the pump is less prone to short cycle, and also works nicely when the power is out so you can still flush toilets, wash hands, get water, etc.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

Here is my tank though the picture makes it look too tall. Maybe the picture is just wrong.

https://www.amazon.com/Amtrol-WX-250-We ... B0057P21GO

44 gallon.

Says factory pre-charged pressure at 38 psi. Trying to pull up manual because technically the pressure should vary based on the system pressure range. But something tells me 38 is about perfect for the set points of my system.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

Gee this sounds familiar!
The amount of water delivered between pump cycles is called drawdown. The larger the well tank, the greater the drawdown capacity, the less the pump needs to run. This saves energy and money, and extends pump life. Larger tank sizes also increase the water storage volume to provide more consistent water pressure.
Yup again.
Adjusting Precharge Before Installation
Step 1. Remove protective air valve cap.
Step 2. Check precharge pressure (pressure should be + or - 10% of the 38 psig factory setting).
Step 3. Release or add air as necessary to make the precharge pressure 2 psig below the pressure switch pump cut-in setting. (Example, if you have a WX-202XL with a precharge of 38 psig, and you have a pressure switch setting of 30/50 psig, adjust precharge of your WX-202XL from 38 psig to 28 psig.)
Step 4. Replace protective air valve cap.
So mine cuts in around 40 psi. So 38 psi is perfect (2 psi below cut-in pressure). I should double check with no water system pressure since it has been 3 years and last time I checked there was water pressure, which is an invalid way to measure...
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

kevm14 wrote:What I did was run my kitchen sink into a 1 gallon container and time it. Turns out it flows at almost exactly 1 GPM (I'd rather 2.5 or so but it saves water I guess).
Great news everybody! I installed that higher flow screen on my kitchen faucet. My flow went from 1 GPM to 1.5 GPM, which is obviously a 50% increase. It is very noticeable. My results were measured. I think the old screen was probably rated at 1.5 and the new one at 2 or something. My well pressure settings are a bit lower than normal city water hence my results.

Oh, this is fun. Here is how much junk was trapped in the old low flow screen after THREE YEARS with zero well water filtration:
WP_20180707_20_20_44_Pro.jpg
Even I'm surprised. That's not bad at all.

And here is the new, higher flow screen:
WP_20180707_20_22_17_Pro.jpg
I was going to wait for the new kitchen (yes I am reusing this faucet because it was expensive and is only 3 years old) but I was getting annoyed at the low flow. Filling a bucket to wash the STS was so annoying.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

I guess I forgot to post that I fooled around with the pressure regulator. I ended up bumping the pressure up to the 55/75 range. 55 psi cut in and 75 psi cut out. I figured a nominal pressure of 65 was "normal" and much better than the original 30/50 or so that it had. Of course, I am not sure this was a good idea as I ended up with a leak here and there on some old shutoffs in the basement. I fixed those. The reason I bumped pressure up was because I was anticipating installing a whole house filter and figured there would be a little pressure drop through the filter. Of course I also adjusted the pressure in the pressure tank to 53 psi (spec is 2 psi under cut-in pressure).

Fast forward to recently and I had been noticing strange pressure flucuations. It was most noticeable in the shower because the pressure fluctuation would cause the water to be momentarily too hot or too cold. You could also notice it when flushing a toilet at times. I decided to investigate.

I ran the kitchen sink and monitored the well water pressure. What I found was when the pressure got down to the 55 psi cut-in pressure, the pressure would actually plummet very quickly just as the pump was turning on. Or just before. Hard to say. My first thought was that the pressure in the tank could have gone down and it wasn't storing pressure properly. But when I put a gauge on the tank, to my surprise, the pressure spiked my gauge, which tops out at 60 psi! I shut the house water off and connected a hose to the drain at the well tank and made sure the water pressure was low. Yep, pressure still way too high in tank! How is that possible?

So I let air pressure out until it got down to 53 psi and tested everything again. It seems fixed now. Seems like this won't be the end of this but for now I guess I'll run with it and see how things behave.

FWIW, when I ran pressure down with the pump off, I never saw any brown garbage come out of the well. That surprised me as well.
kevm14
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Re: Well pump pressure experiment

Post by kevm14 »

I think I busted my new gauge when I initially measured the tank and pressure spiked the gauge past the 60 psi limit. I think it reads 3+ psi low now. Consequently I think the water pressure issue is not totally gone. So I ordered a new gauge which is similar to the old one but it has a cool hose and goes to 100 psi.

Turned the pump off, ran the kitchen sink until the water pressure dropped. Tank was STILL over 60 psi!! So I let air out (took a while) to get down to 53 psi. Hopefully now it is good.

Just flushed toilet. Still did it. WTF is going on? To be continued.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

It seems like the pressure tank pressure keeps increasing??? I have no explanation for this. Would air in the inlet water (on the other side of the diaphragm) have a similar effect?

If I am getting air that means my well pump needs to be lowered....OR, that there is a rupture in the pipe. I guess I'll keep ignoring this until something gets worse. But it is possible that I will need a well company to take a look at this at some point.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

It's still doing it. Found the tank at 60 psi again. I set it at 53 psi last time. This is so weird.

Decided my pressure experiment has failed and backed it down 5 psi to approx 50/70. That provides a nominal pressure of 60 psi which sounds totally normal to me, at least for city water. Should give the pressure tank a bit more capacity at the lower pressure as well.

I dropped the pressure tank to 48 psi of air. A brief test reveals that the pressure is not dropping suddenly as the well pump kicks on but time will tell. It could be what happens is the air to the tank goes up (because something is wrong, but not sure what), and eventually the tank runs out of reserve diaphragm pressure before the well pump cut-in. I feel more comfortable at the lower pressure and I'll drop it another 5 psi if I have a reason to do so. I still can't explain why the diaphragm appears to increase air pressure over time. When they fail, it's usually the opposite problem. The whole tank just holds water and the measured air pressure with no water pressure would be zero. Mine is also clearly storing water pressure.

By the way, 70 down to 50 psi can't even fill two car wash buckets. Not sure if that's normal either. Has to be less than 8 gallons and it is a 44 gallon tank. Of course, operating capacity is said to be roughly half the spec (since half is air and half is water). But I'm less than half of even 22 gallons. So I still think something is up with the tank.

EDIT: or not?

https://www.amtrol.com/wp-content/uploa ... T-card.pdf

A quick glance at the table shows I was off on what I remembered about the capacity. Originally the well installer left the pressure switch at the default 30/50. The drawdown capacity of the WX-250 tank is only 13.6 gallons even at that low pressure. At 40/60 it is 11.8 gallons. And at the 50/70 I currently have it set to, drawdown is 10.4 gallons. Suddenly, that doesn't seem far off at all. FWIW, that's as high as the spec goes, at least in this quick sizing reference. I was operating higher than the highest rated cut-in/cut-out pressure (granted, only by ~5 psi). I'll report back with more data when I have something. Ideally, this thread is closed forever but it seems almost impossible for me lowering the well pressure switch down 5 psi could have this large of an effect on the whole system. Maybe?

https://inspectapedia.com/water/Pressur ... Adjust.php
Screenshot_20221024-104615.png
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

It's less than 4 gallons. So I'm still at 50% capacity. I aired down the tank completely and aired it back up. It's the same. I'm not sure what else I can do at this point but the tank now definitely stores water pressure beyond the pressure switch cut-in point, which should prevent those pressure dips we were having. I'll monitor and if there is any more weird behavior I may drop operating pressure down another 5 psi to 45/65. For now it is around 50/70.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Well pump pressure experiment

Post by kevm14 »

I heard it do the thing when a toilet flushed this morning. There might be a leak in the well pipe that drains some pressure out. I don't think that explains why pressure would drop suddenly as the pump kicks on. The pressure tank's job is to prevent that. And it was working yesterday. I think if I checked air pressure, it would be too high already, which WOULD cause the issue (I think). What I can't explain is what could possibly cause air pressure to increase in the tank. It seems impossible.
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