Water pump on/off every 3 seconds

Damn. I didn't consider a filter in the system. That is a common cause of low flow even when the tank is operating correctly.

Now that you have a air pump, start over. Drain the tank, add air to

Harry K

Hey Einstein. . could u pleeease highlight the part where i gave advice ? ? ? pretty sure that i asked a question. . .

Try post #3 above. That was about as bad as the one I replied to.

Harry K

Too high.

Look, this isn't rocket science. Your pump control is set to come on at 42 psi, and shut off at 58. So shut off the power to the pump and drain the tank, completely. Pressurize the tank to 40 psi. Turn the pump back on.

That's all.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter by sending email to autoresponder at filterinfo-at-milmac-dot-com You must use your REAL email address to get a response.

It is working OK with that pressure. If I drain the tank and pressurize the tank to 40 PSI and then turn the pump on, the pressure will be even higher. The first time I drained the tank, I didn't pump any air in. The second time I pumped it up to 11 PSI, turned on the pump, and it compressed the air until it was at 46 PSI. The third time I drained it and pumped it up to 20 PSI, then turned on the pump and the air pressure went up to 62 PSI.

After using it for more than a day, the air pressure is still at 62 PSI when the pump cuts off. And to check to see if the gauge is wrong, I used a different one and it reads 63.5 PSI.

No, the pressure will NOT go higher. The control switch is set to cut off at about 62 psi. It will do that whether you have 1 psi or 40 psi for the precharge. 62 is where it will cut off. It will also start at about 40 psi no matter what your precharge is. The precharge is not what operates the system. The system operates only on the 20 psi differential that the pump adds on top of the pre-charge. The pre-charge is there to for two reasons.

1. Air bubble to compress to make the system work.
2. To control the cycle time of the pump. Anything less than the optimum (2 psi approx below cut-in) makes the pump run more often for less time. That is hard on pumps.

Trust us. I don't know about Doug but I have been running these systems since I was 16 and am now 70 still running them. Shut the pump off, drain the tank and pump the proper amount of air in.

Harry K

Well, it did the other three times.

The first time I drained it, I let the air pressure off and didn't pump any air in. After I cut the pump back on, the air pressure in the top of the tank was around 20 PSI, but I don't remember the exact figure.

The second time I drained the tank, I pumped the air up to 11 PSI. Then I turned the pump on, and the air pressure went up to 46 PSI. After the pump went through , it maintained 46 PSI (when the pump cut off).

The third time I drained the tank, I pumped the air pressure up to 20 PSI. After turning the pump back on, the air pressure went up to 62 PSI. Three days later, when the pump cuts off, the air pressure is still around 62 PSI.

So, to summarize: air pumped in / final air pressure:

before final

If I drain the tank, pump up the air to more than 20 PSI, and then turn the pump on, the final air pressure is going to be higher than 62 PSI. I'm willing to take bets on that.

It has twice been said that this isn't rocket science, but there is physics involved - Boyle's law. As a gas is compressed onto a smaller volume, its pressure goes up.

Yeah, but the pump is supposed to be cutting off at a specific pressure, so boyles law or not, the upper limit should be constant. If it's not, then there's something wrong with your setup. Specifically, if you pre-pressurise the tank to or beyond what the upper cutoff is, the pump should never come on at all.

According to Harry K :

Interesting.

The reason I say that is that the bladder-style tank we have isn't very big at all. It's about 14" in diameter, about 24" tall, and probably weighs about 15 pounds empty. That handles us without any problems whatsoever. (simultaneously taking a shower, flushing the toilet, running the dishwasher, and clothes washer when the irrigation system is in operation! Okay, yeah, we couldn't take the shower without a pressure balance valve...)

A _large_ tank (ie: anything approaching a hot water tank in size) is suggestive of either an old-fashioned bladder-less tank, or cistern requirements (ie: very low flowrate well).

According to Harry K :

Or what I did once. In a hurry to test whether the new water pump was working in a new house, I wired it up, and only did enough plumbing to get it to the tank.

Fired it up.

Hey, cool, it works!

Now _how_ do I empty the tank?

I almost got away with partially cracking open a 1/4" NPT plug on the meter manifold and deflecting the spray into a bucket. Until the plug fell out.

FWOOMMP!

There were a number of very upset (wet) people on the other side of the basement.

According to Michael Strickland :

As a FYI, another "odd" pump cycling cause: the tubing from the line to the pressure switch gets plugged with crud.

You'll think the pressure switch or pump was defective, because sometimes the pump fires up, and sometimes it doesn't.

According to snipped-for-privacy@uri.edu :

Exactly.

He's showing erratic operation. No matter what he precharges the tank to, the peak pressure _should_ be the pressure switch cut-out pressure.

Which suggests to me that something is wrong with the pressure switch setup, and the pressure switch isn't seeing the true line pressure.

If the unit has a small hose supplying the pressure switch, take it off, and ream it (and the fittings) out with a pipe cleaner.

The pump does cut off consistently at 57-58 PSI of the WATER. The AIR pressure at the top of the tank at that point depends on how much air I put in when the tank was drained. The more initial air, the higher the air pressure.

The bladder may be broken, but it is holding the air pressure.

Correct me if I'm wrong, but isn't there a diaphragm or bladder made out of rubber or something like that in the tank, with air above it and water below it? When the tank is drained, there is no water in the tank and pressurizing the air in the tank via the valve at the top pressurizes the air above the diaphragm, but not below, right? (It doesn't pressurize the whole tank, just the bladder, right?) Then the pressurized air doesn't affect the water going in until it hits the diaphragm, right?

There is a 3/4" pipe coming off the main pipe that goes to the pressure switch, and there is a circular pressure gauge coming off that pipe. The pump cuts on and off consistently according to that gauge. I'll have to drain the tank again to clean it out.

O.K. I think I see why you are misunderstanding the system. The pressure in the tank is initially set by the pre-charge. The switch will be set for a specific cut-in/cut-off. The pump starts and will add about 20 psi to whatever pre-charge you put in and then cut off when system pressure reaches the cut-off (62psi). Here is a basic step-by-step.

Tank empty

You now have a tank containing water and an air bubble that is now compressed to 60 psi.

you draw water. Tank empties down as the air bubble expands System pressure reaches 40 psi. Pump cuts off. At this point the air bubble has decreased only 20 psi System repeats until something fails.

Your basic misunderstanding in your post is that the water is compressed. No it is not, water cannot be compressed. The air bubble, whether separated from the water by a bladder or not is what makes the system run and is the only thing having pressure. Yes, it does compress the bladder and thus presses on whatever is in the tank, i.e, the entire tank both above and below the bladder senses the same pressure. When the tank is empty the bladder will probably be resting on the tank bottom with no water at all in the tank.

When you clean out the pipe to the pressure switch (should be a 1/8" or 1/4" pipe) then re-pressurize the tank to about 40 psi (I think you said it cuts off at 42psi). Watch the gauge. You will see it happily cranking along between 40 and 60 psi (okay, a bit higher at your settingss). Ignore testing teh pressure via the air fill valve on the top of the tank other than when adding the pre-charge. It will always be the same as the tank guage within the error range of the instruments you are using.

Erratic operation could also be caused by a sticking pressure switch.

Harry K

Which is a violation of physics. In a closed vessel with liquid and/or gas components, ALL of it will be at _exactly_ the same pressure at any given moment. The presence of the diaphram can essentially be ignored (if the diaphragm is in contact with both components).

If you're reading a different pressure for the air and the water, either your measurements are defective, or the points at which you measure the air and water do not have a free flow of _pressure_ between them. Ie: there's a plug.

Right.

Right.

Right.

Right. Once the wqater hits the diaphragm, however, the water and air pressure will be the same (within half a PSI).

So, if you're reading 68PSI on the air, and 50-ish PSI on the water when the pump kicks out, something _very_ wierd is going on. I"ll bet on the laws of physics being respected ;-)

I know that water can't be compressed, I said that as water filled the tank, it compressed the air at the top.

It is a 3/4" outside diameter pipe going to it, but it has a connector like this:

Maybe so, but it will work better with correct pressure.

Of course it will. The air is compressed by the water being pumped in. When the pressure reaches 58 psi (the cutoff setting on your control), the pump will shut off. That's how it's supposed to work.

Indicates abnormal operation.

Fine with me. How much do you want to wager?

There's _no_way_ that the pressure is _ever_ going to go higher than the cutoff setting on the well control, unless the control malfunctions.

And as soon as the pressure reaches the cutoff setting on the well control, the pump shuts off, and the pressure goes no higher. If that does _not_ happen, then you need to replace the control unit, because it's malfunctioning.