Pressure Tank or Well Pump Issue?

[Stoogesman]

Hi all. A few days ago I noticed that my well pressure tank is only holding about 1.5 gallons of water. The pressure tank was replaced 15 years (I've owned the home for 4 years). So after hours of researching and learning how a pressure tank works, I performed my in depth diagnosis. Here's what I did:

• Drained the tank completely
• Checked what pressure switch type, which was a 40/60 switch
• Cleaned the pipe sitting between the well water coming in and the pressure switch. I was 90% narrow with build-up
• Replaced the pressure switch
• Filled the pressure tank up to 38 PSI

When the tank was empty I gave it a good shaking and verified it was not water logged and was in fact empty. When the tank was full, I let some air out via the Schrader valve and no water came out. Both of these indicate the pressure tank is OK.

Once all those things were done and the tank filled back up and the pressure was around 50 psi, the same problem existed. The tank will only fill up about 1.5 gallons. The pressure tank is an Amtrol 20 gallon tank.

Here is a video of how the pressure tank/pump are acting when I have a water source turned on, such as a toilet or utility sink:

In summary, the pump is kicking on when called on, the pump is pumping water nicely, the pressure in the pressure tank is rising correctly, but the tank doesn't want to fill up correctly. This is the only symptom I have. The pump isn't turning on out of no where, the tank is holding pressure indefinitely. Could it be the pressure tank over the 15 years of its life is filled with sediment and not allow it to fill to capacity. One thing to also note, when the pump kicks on my water pressure is better than when it's just coming from the pressure tank. When the tank uses its 1.5 gallons, the pump kicks on and my water pressure is really good. Once the pump kicks off (prematurely), the pressure is OK but not as good as with the pump running.

With me not seeing the typical symptoms of a failed pressure tank, could it still be the pressure tank? I've ruled out the pressure switch. So at this point it's either the pressure tank or the pump. Any insight would be amazing. Thanks!

 

[Reach4]

k was empty I gave it a good shaking and verified it was not water logged and was in fact empty. When the tank was full, I let some air out via the Schrader valve and no water came out. Both of these indicate the pressure tank is OK.

The first one is a good test, but the air valve is on top, so you would not output water until much further along.

How much water pressure do you have a minute after the pump shuts off?

 

[Sponsor]

 

[Stoogesman]

The first one is a good test, but the air valve is on top, so you would not output water until much further along.

How much water pressure do you have a minute after the pump shuts off?

The water pressure is OK, nothing to brag home about. But when the pump kicks on, I can feel much better pressure while the pump is running and filling up the tank to it's 1.5 or so gallons. Then once the pump shuts off, the pressure goes back down to OK.

 

[Stoogesman]

Also, just to note, on Friday, I drained the tank completely, then let all of the air out through the Schrader valve. There was no sloshing water in the tank. I filled it back up to 38 psi, kicked back on the breaker and same issue of only filling to 1.5 gallons.

I could be totally wrong, but if the pump was failing, I would think I wouldn't have really nice pressure when the pump kicks on as I'm running a faucet or the shower.

 

[Stoogesman]

Here's a video I just took of the pump kicking on when the pressure dropped to around 39ish PSI. The pump ran for about 32ish seconds and then turned off. So the pump is obviously trying to push water into the pressure tank but after the pressure tank water level reaches a certain point, which is 1.5 gallons, the pump kicks off.

https://studio.youtube.com/video/WG1jseRsnl8/edit

 

[Reach4]

The water pressure is OK, nothing to brag home about. But when the pump kicks on, I can feel much better pressure while the pump is running and filling up the tank to it's 1.5 or so gallons. Then once the pump shuts off, the pressure goes back down to OK.

How much water pressure, in PSI, do you indicate on the pressure gauge a minute or more after the pump shuts off, and before you use water?

 

[Stoogesman]

How much water pressure, in PSI, do you indicate on the pressure gauge a minute or more after the pump shuts off, and before you use water?

Right around 50 psi. Tank maintains the pressure until I draw water.

I've had camera on the pressure gauge for days and it holds pressure all night and day, etc.

 

[Reach4]

t around 50 psi. Tank maintains the pressure until I draw water.

That may say your pump may be shutting off early. That would explain you only getting less water out of the tank. You would expect about 5 gallons.

But another possibility is the check valve at the pump is closing slowly. So your pressure rises to 60 psi, but a bunch of water runs backwards.

So to distinguish watch where the pressure peaks, perhaps taking a movie to let you study.

Another possibility is that your water pressure gauge and water pressure gauge have very different calibrations.
1. When you drop the water pressure to zero, does the gauge go to zero?
2. When the pump is not running, but the gauge shows over 30 psi of water pressure, what are the air pressure and water pressures? They should be close, and if not, there is a significant calibration difference. At least one gauge should be replaced in that case.

 

[Stoogesman]

I hope it's not my pump. I have a well guy coming out tomorrow and he said most times it's the pressure tank but small chance it could be the pump.

 

[Valveman]

Anytime the pressure gauge moves (jumps) that fast, the tank is bad. You have water in the air chamber, and the tank can barely take 1.5 gallons of water. That quick bouncing is killing the pump. It has been killing the pump worse and worse for a long time. Stop the cycling and you may get a little more time out of the pump. But after a pump has been treated that way you are on borrowed time. The problem was/is, a 20 gallon tank only holds 5 gallons of water. Cycling for every 5 gallons used will/has greatly shortened the life of the pump. A Cycle Stop Valve will save a pump and only needs a 4.5 gallon size tank. Without a Cycle Stop Valve you would need a couple 86 gallon size tanks to get anywhere close to the same pump life as when using a CSV.

 

[Bannerman]

Although Valveman is most likely correct, a further possibility is the Tank Tee may be partially blocked with sediment or rust.

A vertical tank is less susceptible to becoming filled with sediment compared to a sideways mounted tank, due to the water inlet/outlet connection being located on the bottom of a vertical tank, thereby resulting in the sediment to be pushed out with the water that exits before the pump becomes activated each cycle.

I said 'partially' blocked as your pressure gauge immediately rises an extreme amount once the pump is activated, and immediately drops to ~50 psi (higher than the Cut-In pressure) once the pump is shut down. This indicates only some small amount of water had entered the tank while the pump was operating, but was not at a sufficient flow rate to cause the tank to fill before the pressure switch sensed the cut-out pressure and shut down the pump. If water is entering the tank as fast as the pump can deliver, I would then expect a small pressure rise above 40 once the pump is activated, and further pressure rise to gradually occur until the pressure builds to 60 psi. Once the pressure switch shut down the pump @60, the pressure should not drop whatsoever while no water is being utilized.

Water will not exit from the tank's Schrader valve unless the tank's air chamber has filled to the top with water.

 

[LLigetfa]

I suspect the water and air pressure gauge is reading wrong and you are are pre-charging too high. You need to calibrate the two.

 

[Reach4]

Anytime the pressure gauge moves (jumps) that fast, the tank is bad.

I think that nails it.

Although Valveman is most likely correct, a further possibility is the Tank Tee may be partially blocked with sediment or rust.

That blockage would have to be on the pipe into the tank.

When the tank was empty I gave it a good shaking and verified it was not water logged and was in fact empty.

My suspicion is you are stronger than you thought, and the tank is largely waterlogged.

 

[Bannerman]

I suspect the water and air pressure gauge is reading wrong and you are are pre-charging too high.

Stoogesman, when checking the pressure tank air pre-charge pressure, are you measuring the pre-charge pressure with an accurate tire pressure gauge on the tank's Schrader valve, after the pump has been de-powered, and after the tank has been fully drained of water?

After checking and adjusting the air pre-charge pressure, and after the pump is reactivated to cause the pressure to build for the PS to turn the pump off, while no water is being consumed anywhere so the pressure will remain stable, have you utilized the tire pressure gauge on the tank's Schrader valve, to compare that reading against the water pressure gauge reading?

 

[Bannerman]

That blockage would have to be on the pipe into the tank.

Correct! That pipe into the tank, is part of the brass tank tee as shown in the video. That connection with the tank, will also utilize an elbow directly below the tank connection.

 

[Stoogesman]

Final diagnosis is in...

It was in fact a bad pressure tank. Just had a new V100 installed and it now pulls 7+ gallons of water before the pump kicks on. Well pump is running strong. She's 37 years old.

 

[Reach4]

Correct! That pipe into the tank, is part of the brass tank tee as shown in the video. That connection with the tank, will also utilize an elbow directly below the tank connection.

If that were the case, with the pump off, and the pressure tank with whatever water it can hold, I would expect the drain valve would put out a bunch of sediment.

It is common that a pressure tank being flushed delivers some colored water with crud; it is not common to have several tablespoons of solids.

Precharged Pressure tank flush:
1. Connect a hose to the sediment drain valve, and run that to where you plan to drain the water. I suggest filtering the output through a cloth if you suspect the sediment may include sand. A tub under the drain spigot could be useful to collect solid sediment directly if there is enough clearance.
2. Turn off the pump.
3. Open the drain valve, and let it drain until the water stops. It would be possibly interesting to watch the first water that comes out.
4. Close the valve, and turn the pump back on, and let pressure build.
5. Repeat steps 2, 3 and 4 as needed.

 

[Stoogesman]

If that were the case, with the pump off, and the pressure tank with whatever water it can hold, I would expect the drain valve would put out a bunch of sediment.

It is common that a pressure tank being flushed delivers some colored water with crud; it is not common to have several tablespoons of solids.

Precharged Pressure tank flush:
1. Connect a hose to the sediment drain valve, and run that to where you plan to drain the water. I suggest filtering the output through a cloth if you suspect the sediment may include sand. A tub under the drain spigot could be useful to collect solid sediment directly if there is enough clearance.
2. Turn off the pump.
3. Open the drain valve, and let it drain until the water stops. It would be possibly interesting to watch the first water that comes out.
4. Close the valve, and turn the pump back on, and let pressure build.
5. Repeat steps 2, 3 and 4 as needed.

How often should I flush my tank? The tank that was replaced today was 15 years. I've owned the home 4 years and I'm sure the previous owners never flushed it.

 

[Reach4]

How often should I flush my tank? The tank that was replaced today was 15 years. I've owned the home 4 years and I'm sure the previous owners never flushed it.

Your question is very rare. The few people that recommend a schedule seem to call for annually -- the same as the recommendation to check/adjust your air precharge. But the manufactures pretty much suggest checking precharge annually, they don't seem to offer a recommendation for flushing. https://blog.twinsprings.com/wp-content/uploads/2014/09/How-to-Flush-Well-Pressure-Tank.pdf does suggest annually.

On the other hand, if you do each every 5 years, you are probably doing them more often than most people.

So maybe I would suggest that you do both in 1 or two years, and based on what you see, adjust your schedule. If you saw a bunch of black crud during flushing, you would be inspired to do it more often.

While discussing scheduled maintenance, there is well and plumbing sanitizing. I do that maybe every 3 or 4 years, but I do a good job of it. https://terrylove.com/forums/index....izing-extra-attention-to-4-inch-casing.65845/ is my procedure. It is more rigorous than most. If planning that, I would order the inexpensive pH meter and high-range chlorine test paper/strips in advance. After doing well and plumbing work is a good time, but it is much nicer to do in warm weather.

 

[Stoogesman]

Awesome info!

The best part is my water pressure is beautiful now. I never considered it bad by any means but now she's coming out with nice flow!! $1000 well spent.