Water Pressure issue

[bartman99]

Hi,
I am having a problem with my water pressure. Water tank and switch are ~20 years old. Well pump is about 5years. Problem is the water pressure intermittently drops to zero or near zero.

Yesterday I checked out my system. I adjusted the tank air pressure to about 35-38 PSI, and the cut on to about 42 and cut-off to around 62. Everything worked fine for a couple of hours. Then the pressure started getting wonky. Here is a video

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of the tank and pump cycling. As you can see and hear, the cut-off/con-on are about right. Immediately after the cut-on, the pressure suddenly drops to near zero (about 10psi in the video, sometimes to zero.)

Any suggestions? Do I need a new tank or switch? Hopefully, I don't need a new well pump!

 

[Reach4]

It is not clear what the problem is. You may have more than one problem. The most remarkable part is how fast the pressure rises, and how fast it drops. What happens if you don't use water? I see a valve on the lower left, which I presume goes to the house. If that is the case, try closing that. If instead that goes to the pump, don't close it.

The single failure that I am picturing is that the check valve at the pump failed. When the pump turns off, the water flows back down. Then it takes a while to turn the water around again. I am not that comfortable with that.

The delayed pressure switch reaction can be due to the nipple to the pressure switch being gunked up or the pressure switch itself being gunked up... making it slow to react.

I am not a pro. Maybe somebody with experience will have a better assessment.

 

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[bartman99]

If I don't use water or close off the water to the house, the pressure is static

 

[Reach4]

If I don't use water or close off the water to the house, the pressure is static

Good.

Your pressure tank has probably gone bad, and the pressure switch or nipple is suspect. Replace them.

For now, you can get a little more time out of your pressure tank by adding air, but it will not last.

 

[Valveman]

It looks like you may just have too much air in the pressure tank. The nipple to the pressure switch is not clogged, as the switch clicks at the right pressures. The hesitation is either a bad tank, too much air in the tank, or you have a delay in water coming up from the well. Let some air out of the tank and see if that changes anything. If not then remove the above ground check valve, and I bet you will see the water pressure decreasing even when not using any water, as the bottom check is not working or you have a hole in the drop pipe. Either way the problem was caused by all the cycling on and off over the years, and now there are ways to stop pumps from cycling.

 

[LLigetfa]

If there is too much air in the bladder, the tank will be empty at about the time the cut-in pressure is reached explaining why the sudden drop in pressure. A common mistake people make is to assume the air pressure gauge they use reads the same as the water pressure gauge.

If what Cary suspects is true, that the lower checkvalve in the pump has failed, the upper checkvalve can create a partial vacuum in the line that then needs to be filled before water reaches the tank. That causes a short delay. Checkvalves work better if they have pressure pushing against them so having more than one checkvalve in series is asking for trouble. You may find that removing the top checkvalve will restore proper sealing of the lower one.

 

[Reach4]

I think we can all agree that in addition to some other problem(s), the pressure tank is shot.

To confirm that, a drawdown measurement would make sense. That would be to turn off the water to the house, and let the pressure climb to 62. Then use the tank drain to draw water into a bucket. A good tank should give about 1/4 or so of the nominal tank size worth of water.