Bad pressure tank?


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Old 06-20-20, 10:23 AM
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Bad pressure tank?

We have a well with a Wellmate WM25 tank. I had someone come look at our system, and he said tank was waterlogged And should be replaced.

. From what Iíve read, the pump should short cycle if this is the case.

I let tank fill to 60 psi. Then I turned the boiler drain at base of tank open full blast. It took 45 sec for tank to drop to 40 psi.

I then closed the valve, and it took 2.5 minutes for tank to get to 60 psi. I also pushed the air nipple for a second on top, and only air came out.

Does this sound like normal functioning?

Thanks

Dave
 
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Old 06-20-20, 10:48 AM
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It certainly doesn't sound like a water logged tank.

With your pressure switch there should be 38psi of air in the tank. The way to check it is to shut the pump off, open the water valve to let the system get to 0psi, then measure the tank pressure.
 
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Old 06-20-20, 10:53 AM
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Why did you have someone look at the system?

Is there a problem with it and if yes what is the problem?
 
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Old 06-20-20, 11:55 AM
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Thanks guys. We bought the house a couple years ago. There is an inground irrigation system, and we had done some seeding.

I was concerned about well flow and running it dry potentially. I looked online to calculate gpm with pressure tank. I was able to empty about 15 gallons before pump came on. It then took 2.6 minutes to refill the tank. Per the calculations, it was 5.6 gpm.

I had a well company come to see if there was something that could be done to increase the flow (maybe hydro fracture)?

They evaluated the well and said waterlogged tank and pump having hard time keeping up. Got an estimate of close to $5000 to replace pump and tank.

But since the well is older, there are no records to tell us how deep it is or what it is capable of.
 
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Old 06-20-20, 02:15 PM
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I would not do business with that well company without checking with some others. $5'000 for a new pump and pressure tank is extremely high especially if they don't know the depth of your well.

You did not mention a problem with the output of your well so I'm confused why you want to increase it's "capacity". Running the well dry is sorta a separate issue and is basically pumping water out faster than water can seep into the well and there isn't much you can do about that. The well you have is what you've got. Code does not permit deepening an existing potable water well.

If irrigating you can keep track of how long you are irrigating. Then if you run the well dry you have a rough idea that running sprinklers for an hour is too much. So, next time you irrigate for half an hour then let the well rest for a few hours and finish your irrigation in a second watering.
 
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Old 06-20-20, 02:46 PM
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Could there be something wrong with the tank? The drawdown on that tank is about 27 gals at the 30/50 range, so at 40/60 it would be somewhat less than 27 gallons, but I think just a few gallons less. You only got 15 gallons with your test. I think if the tank was at 60 and then you emptied to 40 and only got 15 gallons something is wrong Ė at least thatís the way it seems to me.

https://www.pentair.com/en/products/...ies-tanks.html

(I defer to Pilot Dane, but my impression also was 5K is really high)
 
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Old 06-20-20, 04:06 PM
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A few gallons either way isn't going to change the situation. The pressure tanks primary job is to keep the well from short cycling. It would be extremely rare for the pump to cycle when irrigating. Typically a pump can just barely keep up with the load.

What needs to be done is to run each irrigation zone and monitor the nominal system pressure.
See if the pump cycles during any one of those zone tests.
 
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Old 06-20-20, 05:29 PM
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The well pump definitely comes on when a sprinkler zone runs. With three heads putting out a total of 9 gpm, it definitely comes on, and I think it stays running. Donít think the tank filled to 60 psi with sprinklers going (until after they shut off).
 
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Old 06-20-20, 09:43 PM
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Don’t think the tank filled to 60 psi with sprinklers going (until after they shut off).
Yes.... that would make sense.

I'm always leery of using a domestic well for irrigation. If you've got a lot of lawn to water you may need to consider a second well for irrigation purposes.
 
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Old 06-21-20, 04:50 AM
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If you are running a constant long term load such as lawn watering, then the well pump will cycle unless the gallons per minute of the sprinklers equals or exceeds the GPM of the pump and well. (If the load exceeds the GPM of the pump then the pump should cycle also, using a run-dry safety cutoff.)

Given that the well is older, there could have been geological and/or hydrological changes underground and it will be necessary to conduct a battery of tests to determine the present day GPM capability. If you are getting plenty of water for household use you would probably not want to spend money improving the well and plumbing as it stands althougy you might want to consider an add-on consisting of a cistern (non-pressurized storage tank) that you fill up overnight and use that during the day for lawn watering.
 
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Old 06-23-20, 11:43 AM
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Thanks for all of your advice and answers. Assuming the bladder is not ruptured, why would I get a drawdown of only 15 gallons before pump came on? From the specs, it says drawdown at 30/50 is approximately 27 gallons.
my tank has bladder pressure when empty of 38 psi and pump is set for 40/60. Thanks
 
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Old 06-23-20, 02:50 PM
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Is your pressure tank marked with the model number or size? If not are certain you are looking at the correct specs for your tank?

How did you determine that your tank has a tidal capacity of 15 gallons? Earlier you said it was "about". Did you fill buckets and measure the 15 gallons? If you are not sorta accurately measuring then you don't know. I'm not being nit picky but if your just opening a faucet and guessing you might not have a equipment problem.
 
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Old 06-23-20, 02:59 PM
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Yes. Pressure tank is WM25. It holds 86 gallons. At 30/50 settings for pressure switch, drawdown is 26.7 gallons. Mine is set at 40/60. I filled tank With water until switch shut off at 60 psi. Then I attached a hose to the drain. I was able to completely fill a 5 gallon bucket almost 3 times before pump came on. So it was a gallon or so less than 15 gallons.
 
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Old 06-23-20, 04:23 PM
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I had my 35 y/o pressure tank replaced last week. The old tank was original to the house and still held pressure. I had a plumber in the house and thought it was a good time to replace the tank. He installed a new 26G tank including a new switch and piping for $500. It took him about a half an hour. So I think $5K for a tank and well pump is probably a rip off. Find a new well company.
 
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Old 06-24-20, 08:01 AM
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Mine is set at 40/60. I filled tank With water until switch shut off at 60 psi. Then I attached a hose to the drain. I was able to completely fill a 5 gallon bucket almost 3 times before pump came on. So it was a gallon or so less than 15 gallons
.
Thatís the way I test mine also. To me that seems like a foolproof way to check the drawdown. I donít see what could be wrong with that logic.

I wonder if somehow the bladder (I believe that tank has a bladder) isnít expanding all the way. At the link below they talk about bladder problems - but they are talking about a new tank. But still, why couldnít something like that go wrong with an older tank? I think I've heard of cases like that with older tanks (not 100% sure though).

But according to Jeremy Rasmussen, an experienced well driller and installer, he sometimes can "un-stick" a jammed or stuck water tank internal bladder by temporarily forcing the well pump to pressurize the water tank to a pressure above the usual pump pressure control switch cut-off setting. Jeremy holds the pump relay switch closed to force the pump to keep running to increase the pressure against the stuck bladder
.
https://inspectapedia.com/water/Wate...ostic_FAQs.php
 
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Old 06-24-20, 10:16 AM
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I can't say this is the case but in theory it should be correct. When you drain your tank to take the measurement of air, on the other side of the bladder, you would also be allowing air to get into the water side of the bladder. Once you turn on the pump the volume on the water side will not be ONLY water, it will be a combination of water and air. It may take a few days or weeks for that air to dissolve into the water or come out of your taps before your drawdown will grow to 27 gallons.

All I have said is just a theory. I have emptied my tank quite a few times and I doubt I saw its drawdown double over the next few weeks but I only have a drawdown of 4.5 gallons so perhaps it was less noticeable. If it changed by a gallon or so I would not be surprised and as I said, technically it should.

I will add that if your theoretical calculations come to 26.7 gallons, you would probably be lucky to see 20 gallons in real life. It just seems to be the way it goes. Also, I think you mentioned that 26.7gallons was for a 30/50 and you are using 40/60. That would make a difference as well. So with all that said, I am not sure 15 gallons is that far off the mark and you may see it rise as the trapped air dissolves into the water and is replaced with more water to drawdown.
 
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Old 06-24-20, 10:41 AM
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I think that there is no such thing as a severely stuck or jammed bladder other than a ruptured bladder, that always requires replacement.

If the bladder has become stuck to itself and prevented water from gonig into the tank then we are only hoping against hope that increasing the pressure a little more will hit the magic number of PSI that will unstick the bladder. I kind of doubt that a bladder will remain stuck to itself over 30 PSI.

But the bladder can herniate, namely rupture and then block the neck so water cannot come out of the tank. This results in unpredictable erratic performance because the water coming out is stopped at random moments and system pressure is lost and the pump starts after a near zero PSI bounce. Replacement is mandatory.

In addition, any ruptured bladder can cause when more and more water to be trapped above the bladder and causing a waterlogged condition when an adequate air cushion cannot be maintained.

If you think the bladder is stuck to itself and you think you want to unstick it by holding the pump switch on, instead let air out of the nipple (Schrader valve) on the pressure tank. You will have to put all that air back in when you are done testing.
 
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Old 06-30-20, 02:39 PM
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I turned off the water supply and drained the tank. The bladder pressure was 22 psi. I hooked my compressor up and filled bladder to 38 psi. Maybe this was why the draw down volume was low? By the way, after I drained the water, the tank was very light, so no trapped water or ruptured bladder.
 
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Old 06-30-20, 03:28 PM
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"The bladder pressure was 22 psi."

Yes that would result in only 15 or so gallons drawn out before the pump started up again.

The pump was still cycling otherwise normally between 40 and 60 psi. Except that 40 was reached when there was still several gallons of water in the tank.

I would guess that last time you preset the pressure tank to 38 PSI there was a lot of water still in the tank.

Since there is no easy way to verify how much water is in the pressure tank, the best way to set a frame of reference is to get almost all of the water out. To do this latter you start prepressurizing the tank while the rest of the system is depressurized with an open cold faucet.
 
 

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