Hi all, here's my dilemma:

I wanted to install a shut-off valve to my outdoor faucet and as part of the preparation, drained the water from the whole house at the base of the water pressure tank. I shut off the flow between the well pump and the water pressure tank, and turned off the power to the pump itself as part of process.
After successfully installing the shut-off valve, I closed the drain at the base of the water pressure tank, re-opened the flow between the well pump and the pressure tank, and then turned the pump back on. Everything started back up just fine, but now the pump cycles on, brings the psi up to about 75, cuts off, and then the psi almost instantly drops to around 25 psi (it takes about 2 seconds), causing the pump to cycle back on. Right now I have the pump turned back off so I don't burn it out, but if I leave it on, this cycle just keeps endlessly repeating. So plumbers - why doesn't my system hold water pressure? I've heard that bladder pressure tanks (which mine is) can cause this if there is a tear or hole in the membrane. Are there any other reasons? What else should I be checking? Thanks in advace!
-Bill

There is an air valve on top of tank. Depress pin in valve, if u get water your tank is no good and has to be replaced. Bladder is broke.

The on off pressure gauge should read only 20PSI difference. If top end, the off reading, is 75PSI, which is high, then the on setting should be 55PSI.

The bladder tank will be set 2PSI lower then turn on,Which in your case would be 53PSI. This is done with bladder tank empty and well off.

Most wells are set with a 60PSI high.

Can u hear water running after reaching shut off point as pressure drops?

Let us know

Chuck

I think your wild pressure swings are due to your short cycling. Hard for the switch to respond so quickly. I wouldn't do anything before checking the tank.

Crea hit the nail on the head about your pressure tank. If you get water out of the air valve on top, then you can do a short term "get by" until you can replace the tank. Turn off the system, drain all water out. Use an air pressure tank to put air into your bladder tank at the top, 15 or 20#. Then restart your system. Short cycling should be gone. But it will return. The only permanent fix is a new tank.

I pushed the pin in a few times like you said - just air comes out. And yeah, I agree, the PSI seems way too high on the high end.

I do not hear water running when it shuts off, and after I turn off the pump, we still have good pressure throughout the house for a while. Not enough for a shower, but enough to run the taps occasionally or flush a few toilets and have them refill. That to me sounds like the bladder may still be intact, right?

One thing I did notice is that the pressure valve at the bottom of the pressure tank is stuck on 50 PSI no matter what happens. I can see why that could be an issue, but don't understand why the pump's pressure valve reading drops to 25 almost instantly...

Thanks for the good tips Chuck. Keep 'em coming!
-Bill

I think you have two problems.

The first is the excessive pressures you are running. Running such high pressures is hard not only on your plumbing but also hard on the pump.
The second is that when you drained the tank using the drain valve you let additional air in the tank. Now you have air in between the bladder and the tank. Now it takes very little water to go from cut on to cut off pressure. I don't know, but I don't think the ratio of volume to pressure is a straight line ratio.

In other words, when pumping up a tire, ever noticed how much air it takes to go from 20 to 25 lbs and how little it takes to go from 40 to 45 lbs. Same thing would apply here. At the pressures you are running it takes very little water to go from cut on to cut off. If it takes 5 gallons of water to go from 30 to 35 lbs it might only take 1 gallon to go from 65 to 70 lbs. Combine that with the fact that you have additional air trapped between the bladder and the tank and you pump comes on every time you flush.

Reset cut on/cut off pressure to 30/50 or to 40/60. Open drain valve and drain tank. With the drain valve open, pump up bladder to 50 or 60 lbs to force out the air between the bladder and the tank.

Close drain valve.

Let out the air in the bladder to 28 or 38 lbs depending on pressures you set on pump switch.

Restart pump.

I think you guys are all onto something, because just as you say, it take a lot longer for the PSI to go from 25 to ~50, and then only seconds to go from 50 to 75.

Also, as a side note, when I knock on the tank, there is definitely a hollow sound on top, and a solid thunk where the water is on the bottom.

I'll keep you posted... and thanks!
-B

Your tank sounds OK. All bladder tanks have air below the bladder when they are first installed. You described a 2 second cycle at first. But in your last post above, it sounds like a longer period (it take a lot longer for the PSI to go from 25 to ~50, and then only seconds to go from 50 to 75.) The stuck gauge also needs to be replaced, but that is not the source of your problem.

If I was you, I'd look at the switch. The little pipe leading to the switch has a habit of getting clogged with crud. This makes the switch respond slowly, which might explain your wild pressure swings.

I would also do a volume test. Your system should be able to deliver at least 5 or 6 gallons between the pump cutting off and then cutting back on. Let the pump run until it cuts off. Run water out of a hose into a five gallon bucket. See how much you get until the pump cuts back on. If it's only a gallon or two, then there is a problem somewhere.

Most switches don't have a 50# interval. Most are around 20#. That also seems to point to the switch. Still, the volume test is, in my opinion, the king of tests for trying to see if your system is performing properly or not.

I think you are right about the tank. I'm pretty sure it is OK. I can't do the volume test with the pump on however because it is almost never off. To be more clear about the cycle, it cuts in around 25-30 PSI and turns off at 75 PSI. It is just that the time it takes to get from 25 to 50 takes about 20 seconds, and then it shoots up to 75 in another 5 seconds. The switch cuts off (I think this must be something like an emergency cut-off?), the pressure drops down to 25 in about 2 seconds, and then the pump immediately cuts in again. So it is on for about 25-30 seconds, off for 2 seconds. I'm starting to think that either the cut-off pressure somehow got raised to 75, or the regular cut-off switch isn't working, and the pump is relying on the emergency cut-off. Then as you said earlier, it the pressure falls so fast that the gauge can't track it accurately enough, it overshoots and so when it hits 25 or 30 on the low side, it triggers the cut-in switch again.

Hmm, correction, it cuts back in around 50, not as low as 25. So I'm trying to adjust the switch down to the 30-50 range instead of 50-75, but the only way to do it seems to be by rotating a screw which adjusts the distance the pressure switch has to move before it makes contact.

Of course, how ANY of this is related to draining the system yesterday is beyond me - lol.

Loosening the longer screw or nut should lower both the cut in and cut off pressures. Adjusting the shorter screw or nut should adjust the range between the cut on and cut off.

So I managed to get the pressures adjusted down to 30-50. At first the pressure was slowly but steadily dropping within those ranges, but now it seems to be holding steady when the pump cuts out. (Filling up the water heater or something perhaps?) Thanks to all for the helpful tips and hints. I will be sure to come back if something else pops up!

And as I said, I have no idea how this was related to me draining the system, but now that it is back working, I shouldn't complain!
Thanks again,
-Bill

Be sure to do the volume test. If you can't get at least five or six gallons, then your problem is not solved. Also make sure your system will hold pressure with the pump off and no water being used.

Almost forgot - I get a solid 5 gallons before the pump kicks in. I checked it twice. However, the system is back to EVER so slowly losing pressure when no water is being used - takes about 5 minutes before it cycles back on with no water being used. Time to check for leaks (I changed the water filter this morning too) I guess?

West, I think your problem might be a leaking checkvalve. Is your pump in the well or above ground?

Do you have a cutoff valve on the pipe going to the house? If so, turn that off, then see if your pressure holds. If it drops, then you likely have a checkvalve problem.