Time to replace pressure tank?

[H22lude]

I've been in my house since August 2018. First house with a well. Wanted to test my well pump and pressure tank. We have a 40/60 pressure switch. It is an Amtrol WP32SS 32 gallon tank manufactured in 2012. I had my wife open the cold side of our basement faucet and let the water drain until the switch kicked on at 40psi. It took 18 seconds to go back up to 60psi. Using that same sink I had her drain it when it got to 60psi. It took 3 minutes and 3 seconds to drain back to 40psi and only at 3 gallons (we also had a silicone hose hooked up to the faucet so it probably wasn't the best test). I then turned off the well power and drained the tank. I measured the air pressure at around 17psi.

I'm just learning about pressure tanks but this seems really bad. From my quick research, going from the cut on to cut off pressure, it should take about a minute. And the air pressure should be 38psi. How can I determine if the bladder is bad or if it just needs air?

 

[Reach4]

Turn off the pump, and drain the water pressure to zero. Presuming you have a submersible (underground) pump, use a compressor to bring the air pressure to 38.

Optionally, with the pump still off, you could wait an hour to see if the 38 psi held.

See if the run time of the pump improves when you turn the pump back on.

 

[Sponsor]

 

[H22lude]

Turn off the pump, and drain the water pressure to zero. Presuming you have a submersible (underground) pump, use a compressor to bring the air pressure to 38.

Optionally, with the pump still off, you could wait an hour to see if the 38 psi held.

See if the run time of the pump improves when you turn the pump back on.

Ok luckily I have a pancake compressor I can use. I'll have to get the valve fitting attachment.

If it holds at 38psi for an hour, why would it have been so low in the first place? Does that just mean the leak is small right now?

 

[Reach4]

If it holds at 38psi for an hour, why would it have been so low in the first place? Does that just mean the leak is small right now?

Hard to say. It's possible that somebody let air out. How could that happen? Somebody decided to adjust the air pressure while the water pressure was non-zero? Kids liked the hissing sound?

 

[H22lude]

Hard to say. It's possible that somebody let air out. How could that happen? Somebody decided to adjust the air pressure while the water pressure was non-zero? Kids liked the hissing sound?

Thanks. I'll bring it back up to 38psi and see how it acts. I assume if it drops again, even slowly, then there is a leak and I'd need to replace the tank

 

[shane21]

If you check the air pressure again in a few months and some air has leaked out you have the option to add air again. A tank that leaks a few pounds a year and needs air added once or twice a year isn't a major issue as long as you don't mind the minimal work to add the air. You can do that as often as needed to keep the air pressure in the tank correct if it's not a nuisance to keep up with it, or you can replace the tank. Leaks don't generally get smaller so it is likely at some point you will be adding air so often that changing the tank may be worth it.

 

[Valveman]

As long as the broken piece of bladder doesn't seal the inlet/outlet hole you can keep adding air to a bladder tank for years. However, the water on top of the broken bladder cannot get out of the tank and will become contaminated and nasty. A lot of times you won't know there is bad water in the tank unless the power goes off. But when there is no power and the tank drains completely it will inject that nasty water into the house.

Bladders or diaphragms in a tank wear out from the pump cycling on and off too much. The bladder goes up and down with each pump cycle like bending a wire back and forth until it breaks.

 

[H22lude]

I just added more air. First I brought the switch up to 60PSI and tested the valve. I opened it with my finger and did not feel any water coming out, which sounds like a good sign.

I then shut off the breaker to the pump and drained the entire system until water wasn't coming out of my basement sink. At the end this water was brown. Is this sediment that is getting stuck in the tank? Is this something I should worry about? I tested the air and it was at 17PSI. I filled the tank until it read 38PSI. I then turned the pump back on until it filled the tank up. I did notice the cut off was no 65PSI. I used two gauges to read the pressure and both said 38PSI. Why would the switch cut off at 65PSI now?

My wife isn't home so I can't test drawn down yet. I did test flow and pressure on my outside spigot. Before filling with air I was getting just a little over 4GPM and 42PSI. Right after filling to 38PSI I got 6GPM and almost 60PSI. The 2 extra gallons per minute is great. The pressure I assume is based on the pressure within the system and that will change whether there is more or less water in the tank. So when the tank is close to empty and going to kick the pump on the pressure at the spigot will be 40PSI and when it is full the pressure will be 60PSI. Is that correct?

I highlighted my questions in red. TIA

 

[Valveman]

Yes the brown stuff was probably crud that was stuck in the tank. If a tank is losing air it is probably letting water on the other side of the bladder where it gets stuck and turns yukky.

The pressure switch should not change But if the tank was waterlogged the pressure change was happening so fast it doesn't really shut off at the right pressure.

And yes when there is 40 PSI a spigot will let out fewer GPM than when the system is at 60 PSI.

 

[Reach4]

I just added more air. First I brought the switch up to 60PSI and tested the valve. I opened it with my finger and did not feel any water coming out, which sounds like a good sign.

Are you saying that you filled the tank that was empty of water to 60 PSI of air? Then you pushed the pin and did not get water? Even with a slightly leaky diaphragm, you would be unlikely to get water from the Schrader valve, because that valve is at the top.

I then shut off the breaker to the pump and drained the entire system until water wasn't coming out of my basement sink. At the end this water was brown. Is this sediment that is getting stuck in the tank? Is this something I should worry about?

There is usually a drain valve at the bottom of the pressure tank. It is usually a good idea to drain the tank with that valve maybe once per year to expel sediment/rust. Turn off the pump. Drain stuff. Turn on the pump. Repeat until sediment/rust stops.

I filled the tank until it read 38PSI. I then turned the pump back on until it filled the tank up. I did notice the cut off was no 65PSI. I used two gauges to read the pressure and both said 38PSI. Why would the switch cut off at 65PSI now?

I am thinking. An explanation not coming to me right now. Watch the cut-in pressure too. Maybe an adjustment to the pressure switch is called for.

My wife isn't home so I can't test drawn down yet.

I don't understand that. You stop using water while the pump is running. When the pump shuts off, you turn off the pump. You leisurely take your 5 gallon bucket outside and fill it. If you fill it, turn off the spigot. Dump the bucket. Add more water to the bucket, and see what percent of the bucket you filled. Not a two-person job.

Incidentally, to compare the calibration of your air pressure gauge and your water pressure gauge, the water pressure and air pressure are normally about the same when the water pressure is near the middle of its range.

 

[H22lude]

Are you saying that you filled the tank that was empty of water to 60 PSI of air? Then you pushed the pin and did not get water? Even with a slightly leaky diaphragm, you would be unlikely to get water from the Schrader valve, because that valve is at the top.

Sorry, no I ran my sink until the switch kicked on at 40PSI. I then let the tank fill and the switch turned off at 60PSI. I then pressed the valve to let air out and see if water would spray out. I would think if water was above the bladder, releasing some air would at least spray some droplets. I home brew and keg my beer. If I have a little water at the bottom of the keg and release the pressure with the pressure relieve valve, I will feel little droplets coming out with the CO2.

There is usually a drain valve at the bottom of the pressure tank. It is usually a good idea to drain the tank with that valve maybe once per year to expel sediment/rust. Turn off the pump. Drain stuff. Turn on the pump. Repeat until sediment/rust stops.

I was going to ask that question. Probably a good idea to check the air pressure in the tank at that time too since it will be drained. So that valve is at the bottom of the tank right on the floor. What is the best way to drain it? Obviously hook up a hose to it but then where would it drain? I have a sink about 25 feet away but the hose would have to go up into the sink. How would the water flow up the house if the pressure switch is getting close to 0PSI? Would the 38PSI within the tank be enough to push it all out?

I am thinking. An explanation not coming to me right now. Watch the cut-in pressure too. Maybe an adjustment to the pressure switch is called for.

I will check the cut-in pressure.

I don't understand that. You stop using water while the pump is running. When the pump shuts off, you turn off the pump. You leisurely take your 5 gallon bucket outside and fill it. If you fill it, turn off the spigot. Dump the bucket. Add more water to the bucket, and see what percent of the bucket you filled. Not a two-person job.

I might be misunderstanding what I'm measuring. I thought I was going to run water until the pump kicked on. Let it fill and stop at 60PSI. I'd then measure the amount of water that came out and stop right when the pump kicks back on. That's not what I should be measuring? If I let the tank go to 60PSI, turn off the pump and then drain the system, wouldn't I also be draining water within the home's pipes?

Incidentally, to compare the calibration of your air pressure gauge and your water pressure gauge, the water pressure and air pressure are normally about the same when the water pressure is near the middle of its range.

Ok so if I'm understanding this correctly, the water pressure I'm getting outside from my spigot will fluctuate depending on the pressure gauge on the tank? That is where a constant pressure gauge would keep the pressure from the spigot the same no matter the pressure from the tank?

 

[Valveman]

Yes the pump needs to be off and the tank empty before adding 38 PSI air to the top of the tank. If air comes out the open faucet, the bladder is bad. A gauge won't keep your pressure constant. You would need a Cycle Stop Valve to do that.

 

[shane21]

One possible explanation for the cut-out pressure being higher on the gauge now that you have the proper amount of air pressure in the system is, depending which type of tank you have, when the diaphragm is low on air is moves farther toward the top of the tank than intended. Some tanks have a steel baffle located higher in the tank that the diaphragm shouldn't reach when properly pressurized with air, but will reach when it is low on air pressure. When that happens the expansion of the diaphragm stops abruptly and the pressure will usually move higher on the gauge very fast, like 10 PSI in a second and the switch cuts out but the but as the whole house system pressure equalizes you will see the gauge drop my some measure immediately after the switch cuts out. I have never seen or heard an actual explanation for the steel baffle but I assume it is to keep a diaphragm from stretching too far and tearing completely.

You won't necessarily feel water droplets leaving the Shrader valve when you release little bit of air, even if there is water in/above the bladder/diaphragm, unless there is a lot of water trapped. A lot of times it is easier to determine if any significant amount of water is trapped by shutting off the pump, draining the tank totally empty of water using the boiler drain (hose connection) at the bottom of the tank, and then just lightly shaking the tank back and forth a bit to listen for sloshing water inside. The hose connection drain at the bottom of the tank can be used to drain the tank through a garden hose into your sink, if a floor drain isn't accessible, and it will work just fine. When the tank has 38 PSI of captive air pressure, the amount of water remaining in that tank after you drain it empty through the hose into a sink that is 3 off the ground is probably a tablespoon or so.

A constant pressure system, whether a VFD, CSV or some other type of system, will give you constant pressure, but it is more than just a gauge. The gauge on any system is nothing more than an output device like a basic monitor on a computer. The only task it performs for the system is to show you what is going on. A system will work the same with or without a gauge but having the gauge allows you to see how it is working.

 

[Reach4]

One possible explanation for the cut-out pressure being higher on the gauge now that you have the proper amount of air pressure in the system is, depending which type of tank you have, when the diaphragm is low on air is moves farther toward the top of the tank than intended. Some tanks have a steel baffle located higher in the tank that the diaphragm shouldn't reach when properly pressurized with air, but will reach when it is low on air pressure. When that happens the expansion of the diaphragm stops abruptly and the pressure will usually move higher on the gauge very fast, like 10 PSI in a second and the switch cuts out but the but as the whole house system pressure equalizes you will see the gauge drop my some measure immediately after the switch cuts out. I have never seen or heard an actual explanation for the steel baffle but I assume it is to keep a diaphragm from stretching too far and tearing completely.

I like that model.

Amtrol calls that feature "multi-dome". https://terrylove.com/forums/index.php?threads/amtrol-multi-dome-feature-of-well-x-trol-and-champion-pressure-tanks.65692/

I was going to ask that question. Probably a good idea to check the air pressure in the tank at that time too since it will be drained. So that valve is at the bottom of the tank right on the floor. What is the best way to drain it? Obviously hook up a hose to it but then where would it drain? I have a sink about 25 feet away but the hose would have to go up into the sink. How would the water flow up the house if the pressure switch is getting close to 0PSI? Would the 38PSI within the tank be enough to push it all out?

I don't know what the best way would be. I have dropped the pressure to zero. Then turned the pump on for 2 seconds. Then drain the water with the drain valve into a pan where I could see any crud. Repeat.

Thinking about it, from a functional point of view without watching for crud, I would empty the water into a hose a few times. Other end could be in the sink. Then carry the hose outside, and flush any crud out of the hose.

Ok so if I'm understanding this correctly, the water pressure I'm getting outside from my spigot will fluctuate depending on the pressure gauge on the tank? That is where a constant pressure gauge would keep the pressure from the spigot the same no matter the pressure from the tank?

I don't understand what you wrote there.

If the pump is off, and the diaphragm and pressure are not at the extremes, then the air pressure above the diaphagm will be very close to the water pressure below the diaphragm. The difference would be if the diaphragm, along with any bellows-like feature, is not totally limp there could be some higher pressure for the water. The diaphragm should be close to limp. But there could be some ballooning. So that water pressure could be a bit higher, or maybe a bit lower if the diphragm is attached higher. But pretty close. The diaphragm is not like a balloon.

But you may be measuring the water pressure with a gauge that is two ft lower than the diaphragm. In that case, the water pressure gauge will see 0.87 psi more. Or the water pressure gauge could be higher in some setups.

So anyway, the pressures will be close. If you see more than 2 psi difference, at least one of your gauges is probably off. That was my point-- you can compare calibration of your tire pressure gauge and your pressure gauge at the pressure tank.

If there is too much precharge pressure, no big deal if you don't have a pressure switch with a low-pressure cutoff. You would just get a quick dip in pressure right as the switch clicks on.

 

[H22lude]

Ok thanks everyone. It seems like everything is working good now. I'll need to keep an eye on the air charge in the tank to make sure it doesn't drop again. If it drops over the next few weeks, I'll most likely have someone come in to look at replacing it. If it stays pretty steady, I'll leave it alone for now. Hopefully I will continue to get 6GPM out each spigot.