Hi,

I just replaced the well water pressure tank. I replaced it because, ever since we moved into our home, the (well) water pressure has pulsed, and someone told me the bladder in the tank was likely bad. After replacing the tank, the problem has continued, and in looking at the way the plumbing is routed, I'm wondering if the problem is the routing, rather than a good or bad tank.

To explain, our well pump is a submersible, in the well. The black well pipe runs from the well to the house, and emerges from the ground in the crawl space. About 6 inches above the dirt where the well pipe enters the crawl space, the well pipe has a "T" in it. The vertical part of this T continues from the well-pipe to the house. The "hortizonal" part of the T runs first to the pressure switch (which is attached to an anti-backflow valve) and then it continues to the pressure tank... which is essentially a "dead-end" of the horizontal T.

This routing makes me wonder if the pressure tank is doing anything at all, since it is after the anti-backflow, and no other line (i.e. -- to the house plumbing) exits the tank. (Hope the rough diaghram below comes through.)

To House
^
|
|
------->----pressure switch and gauge on anti-backflow---------> TanK |
|
|
V
To Well

Your are correct. Your piping is incorrect. The check valve (what you are calling the anti-backflow valve) will not let any water out of the tank. The check valve should be on the well piping before the tee.

When you turn the pump on for the first time water flows into the tank. The check valve prevents it from ever leaving.

When you open a faucet the pressure on the pressure switch drops dramatically. That causes the pump to come on again. You get water directly from the well, not from the tank. However the pump can pump more water than can come out the faucet. Therefore the pressure rises and causes the pump to shut down. Then the pressure drops again and cause the pump to turn on again. Therefore you get a pulsating water flow.

Move the check valve to the well piping before the tee. The purpose of the check valve is to prevent water from flowing back down the well. Most submersible pumps have a check or foot valve built-in at the bottom of the well but it doesn't hurt to have one at the tank. It just has to be on the well piping before the piping to the house.




To House
^
|
|
------->----pressure switch and gauge on---------> TanK |
|
| <----- put anti-backflow here
I
I
V
To Well

I like HK's answer, and it is likely correct, but I must say that this is not making sense to me. I'd sure love to see a pic of this part:

------->----pressure switch and gauge on anti-backflow---------> TanK |

That just sounds strange to me. Again, HK is probably right, but you have described it as though the switch and the checkvalve are somehow attached. That would be really peculiar.

This is how I read this set up.

I think you're right. I just thought this wording was strange:
runs first to the pressure switch (which is attached to an anti-backflow valve)

Hi, Thanks for all your help!

Regarding the "anti-backflow valve", my system has a brass cylindrical "manifold" that's about 6 or 7 inches long and it has several 1/4" threaded holes in it. The pressure switch is screwed into one of these holes, and the pressure gauge is screwed into another. When I found this in Lowe's, they called it a "anti-backflow valve".

I re-routed my system, and this is how it now runs. It seems like my water pressure is lower, but it seems that the pump runs less frequently too, and the pulsing isn't as noticeable. My pump is set at 30/50, and I have 28 PSI in my tank.

|-------------------------Pressure Switch/Gauge---------Bladder Tank------------> House
|
|
C <----- Check valve added
|
|
|
V <---- To well

Regarding the "anti-backflow valve", my system has a brass cylindrical "manifold" that's about 6 or 7 inches long and it has several 1/4" threaded holes in it. The pressure switch is screwed into one of these holes, and the pressure gauge is screwed into another. When I found this in Lowe's, they called it a "anti-backflow valve".

Is that what you are referring to? Man, that's expensive at close to 200 bucks.

http://images.lowes.com/product/converted/098268/098268491401lg.jpg

Hi,

It's a little simpler than that one, but more complex than this one. It's knid of in between the two.

47227

John's image looks like a pressure regulator to me.

Lowe's called it a "backflow preventer", but it does look like a PRV. Hook's pic is just a plain T. It's a mystery!