Water pump / tank question.

[Allan Speers]

As a temporary fix you can pump in some air and the tank will work for a while until the water absorbs the air. You want the tank full of air when empty for best results. When you start the pump it will push water into the tank compressing the air until the pressure reaches your shut off point. WHe you open a faucet you should get a good amount of water out before teh pump starts. This is a temporary fix not a long term one.

Lee, This sounds like you're describing the old "Air over water" type of tank, which I'm pretty sure I have. I'm planning to drain it tonight, and I'm not clear about the air. Once it's empty of water, am I supposed to pre-charge it, the same as with a bladder or diaphram tank? (around 28 lbs) - Or is it supposed to just fill with air naturally, then have the new water create the proper pressure based on the switch's cut-in point?

Also, with this type of tank, why is this a temporary fix? With no bladder or diaphram to rupture, shouldn't it perform as-new once it's drained?

[Lee Schierer]

Lee, This sounds like you're describing the old "Air over water" type of tank, which I'm pretty sure I have. I'm planning to drain it tonight, and I'm not clear about the air. Once it's empty of water, am I supposed to pre-charge it, the same as with a bladder or diaphram tank? (around 28 lbs) - Or is it supposed to just fill with air naturally, then have the new water create the proper pressure based on the switch's cut-in point?

Also, with this type of tank, why is this a temporary fix? With no bladder or diaphram to rupture, shouldn't it perform as-new once it's drained?

If your tank has a bladder that is ruptured, you can fill it with air at room pressure and the water will compress the air giving you some amount of flow before the pressure drops to the low setting on your pump control. The reason it is a temporary fix is that air slowly is absorbed into the water and the tank will become "water Logged" when all or most of the air is absorbed. Normal air over water pressure tank systems have a device that adds a bit of air to the tank each time the pump cycles and also lets out excess air so the tank continues to work. Without this device the tank would eventually lose all its air. The purpose of the bladder was to put a membrane between the air and the water so the air can't escape and you don't need the air regulator which often failed in the old systems.

[Ole Anderson]

The other problem using a tank with a torn bladder is that the bladder may sink to the bottom and block the outlet as the water discharges from the tank. Been there.

[Allan Speers]

Well, I'm still confused, but I did manage to get the system running safely, at least for a short while. If anyone has the time, I sure could use a little more input:
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First, I still don’t know if I have a captive-air (bladder / diaphram) tank, or an air-over-water type. It would really help my diagnosis if I knew. - But the company Clayton Mark is apparently out of business.

My tank has separate openings for the inlet & the outlet, plus it’s REALLY big, so that indicates an air-over-water type. However, It doesn’t appear to have any AVC system, which is supposed to be connected about 1/2 way up. It does have a shraeder valve and pressure gauge, but this is near the top, and also the valve has a cap on it, so this can’t possibly be an air makeup system.


- But if it’s a bladder tank, then my bladder must be ruptured since water came out of the top shraeder valve. - yet I was able to add 38 psi of pre-charge. (se below) Maybe I added that charge to the entire tank? (It sure took a lot of pumping!)

Also, the tank is working again, at least for now. (see below) Could it be that, with a ruptured bladder, the tank is actually operating as an “air over water” tank” and it will eventually stop working again?
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Anyway, here’s what I’ve done so far, and the results:

I drained my tank “almost” until empty. - I didn’t want my pump to lose prime, so I stopped when the water began to trickle.

Then I precharged the tank to 38 psi.

The pressure switch, which is marked 40-60, had been kicking on at about 20 psi, (although with a waterlogged tank) so I turned the main nut a little bit. - It was already near its clockwise limit, but it turned almost one full turn.

I turned the system on, and the pump ran for about 3-4 minutes (which is reasonably within the recommended time) then cut-off at 55 psi. I was happy with this.

HOWEVER, after running the water for a while, the pump does not cut back in until about 27 psi. I can’t adjust it any higher, so I assume the switch is bad.
Also, the gauge right at the pressure switch reads 52, and has not moved a millimeter. Should I assume this gauge is shot?

I am puzzled as to how the tank could even get down to 27 psi, with water still in it, since I pre-charged it to 38 psi?

I also don’t like how the water pressure at the faucets gets lower as the tank pressure gets closer to 30 psi. Is there no way to have true constant pressure? No such thing as a 50 -60 switch, for instance?

[Lee Schierer]

A photo of your system will help clarify what you have. I would guess that your pressure gauge may be bad, which is not uncommon. Typically air bladder tanks have one opening near the bottom or one end for the water to go in/out of the tank. The fact that you have a separate inlet and outlet indicates you may not have a bladder type tank.

1530s.jpg

If you have one of these on your tank:
AirVolumeControl032DJFss.jpg
You do not have a bladder type tank.

Here is a link to a replacement chart for Clayton Mark I believe Clayton Mark makes "Water Worker" tanks.

If your existing tank has a Schrader valve to add air, it definitely was a captive bladder tank.

[Curt Harms]

The pressure switches I've dealt with had two nuts over two springs. One - larger if IIRC was the cutoff pressure. The second smaller nut was the differential. If switch is labeled 40/60 or similar there may not be a differential adjustment. Pressure switches are pretty cheap - Tractor Supply has a 40/60 pressure switch for $18.99. It does sound like you're in for a new pressure tank as well.

[David L Morse]

Well, I'm still confused, but I did manage to get the system running safely, at least for a short while. If anyone has the time, I sure could use a little more input:
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I am puzzled as to how the tank could even get down to 27 psi, with water still in it, since I pre-charged it to 38 psi?

I also don’t like how the water pressure at the faucets gets lower as the tank pressure gets closer to 30 psi. Is there no way to have true constant pressure? No such thing as a 50 -60 switch, for instance?

Reread Ole's post. When the bladder blocks the output the air in the tank is no longer applying pressure to the system. Your symptoms match what I went through a few months ago with my tank, odd pressure readings, low pressure, sudden pressure drops before the pump started and rapid cycling.

The pressure differential on the switch determines the draw down (how much water is removed from the tank between pump cycles). For best pump life you don't want it to start too often so a large draw down is desirable. A large draw down requires a large tank and/or a large pressure differential. It's your choice but if you've ever had to replace you well pump your personal tolerance for pressure changes has probably improved.

Edit: There is a penalty for higher average pressure, a 40/60 switch gives you somewhat less drawdown than 20/40.

[Allan Speers]

Reread Ole's post. When the bladder blocks the output the air in the tank is no longer applying pressure to the system. Your symptoms match what I went through a few months ago with my tank, odd pressure readings, low pressure, sudden pressure drops before the pump started and rapid cycling.

The pressure differential on the switch determines the draw down (how much water is removed from the tank between pump cycles). For best pump life you don't want it to start too often so a large draw down is desirable. A large draw down requires a large tank and/or a large pressure differential. It's your choice but if you've ever had to replace you well pump your personal tolerance for pressure changes has probably improved.

Edit: There is a penalty for higher average pressure, a 40/60 switch gives you somewhat less drawdown than 20/40.

I was wondering about that ! Thanks. I guess that's why I have such a large tank, even though only 1 1/2 bathrooms.


Well, I still don't know what kind of tank, but it's probably an early-style (transitional?) bladder type, since there's no AVC device. I've (temporarily?) stopped the pump cycling, so I'm going to wait a few days and see if the symptoms re-appear, which is likely. At least now I know how these systems work, and am not afraid to install a new one myself.

If the tank is bad, I'm just going to replace everything, since the pump is also ancient. I'd have to replace the stem (with a "Tee" package) pre-tank gauge and switch anyway, so I figure it's almost the same amount of labor, once everything is apart.


Thanks, guys, this has been very helpful. I'll report back when I know what the complete story was.

[Jim Dwight]

It does seem like your pressure switch isn't working right. With respect to the pressure tank design, the only type I know of is with a bladder. I am pretty sure you need that. Even if it is just huge and old, it wouldn't be a bad idea to replace it. Air dissolves in water. I don't see how it can work without a bladder. Possibly a moving diaphragm would work but I would be worried about it sealing. The bladder type seems to work reliably for decade or more in most cases. And they aren't terribly expensive.

I'd replace the pressure tank first and see how it operates. If you still see the pump kicking on at too low a pressure you could replace the switch too. Not having the pressure tank functional is hard on pump and switches, however. The purpose of the tank is to minimize the on/off cycles for the pump and switch. They call it "short cycling" of the pump when the tank fails.

[Allan Speers]

TEMORARY UPDATE:


Well, it's been over 48 hours, and things are still working exactly as they were after I drained & pre-charged the tank:

Cut-in at about 25lbs, cut-off at 55 lbs (definitely need a new switch) And nice, even water pressure. No funny taste in the water.

I still expect things to start going bad again soon, as it's unlikely that I have an "air over water" type of tank, but so far no change at all.



Does this make any sense?

[Lee Schierer]

TEMORARY UPDATE:


Cut-in at about 25lbs, cut-off at 55 lbs (definitely need a new switch)

Take a look at these switch adjustment instructions before replacing your switch.

[David V Carpenter]

I agree with Lee above. And I agree with the people that have said post a photo and piping schematic. Without complete info what you get in responses are best guesses.

Unless you see something wrong with your pump why replace it? Just a thought.

And might I suggest you don't go much higher than 55 psi on the shut off. With the higher system pressure you can get water hammer or you might damage equipment that is not designed to withstand the pressure. You might also install a "tee" fitting in the supply side with a pressure gage. This allows you to monitor performance relative to system pressure and can help diagnose problems.

The larger difference in pressure (between pump start and shut off) results in greater water storage. The closer the set points the less water stored (in your pressure tank). Twenty (20) psi is kind of low and will slow down fill times in your washing machine and dishwasher.

[Allan Speers]

I agree with Lee above. And I agree with the people that have said post a photo and piping schematic. Without complete info what you get in responses are best guesses.

Unless you see something wrong with your pump why replace it? Just a thought.

And might I suggest you don't go much higher than 55 psi on the shut off. With the higher system pressure you can get water hammer or you might damage equipment that is not designed to withstand the pressure. You might also install a "tee" fitting in the supply side with a pressure gage. This allows you to monitor performance relative to system pressure and can help diagnose problems.

The larger difference in pressure (between pump start and shut off) results in greater water storage. The closer the set points the less water stored (in your pressure tank). Twenty (20) psi is kind of low and will slow down fill times in your washing machine and dishwasher.

Thanks, David, but everything I've read says that a 20 psi range is standard. My switch literally says "40 -60" inside the cover, so I assume that's the intended range.

I'll be getting a new switch, regardless, as everything is old, but do some folks actually set a 30 psi range on purpose? (by tightening down the outer adjuster?)

[Larry Frank]

I have a well and pressure tank and end up replacing the tank every 8-10 years. The pressure switch typically last a little shorter time. I keep a spare pressure switch on hand as it is cheap insurance.

[Allan Speers]

I hear you, Larry. I think I'll replace it all even though it's still working. There's quite a bit of corrosion on the outside at this point.

Here's the best pic I could take: