Well pump pressure goes down to zero for a few seconds before pump goes on


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Old 05-09-11, 07:45 AM
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Well pump pressure goes down to zero for a few seconds before pump goes on

I have a goulds 3/4 HP jet pump for what I think is a shallow well. There are two pipes going from the pump to the well, one a bit wider than the other. The pump usually kicks on at 40 and off at 60 lbs of pressure. What started happening is that when the pressure gets close to 40, the pressure drops quickly to zero for a few seconds before the pump comes on. The model is C48A94A06.

What do you think?

thanks,
Joe
 
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Old 05-09-11, 07:52 AM
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It sounds like you have too much air in the tank and the bladder is colapsing. let some air out of the tank. It should be 3-5 psi lower then the cut in pressure.

You know how to check the air?

Mike NJ
 
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Old 05-09-11, 07:57 AM
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Mike,

I don't know how to check the pressure in the tank.

You said, "It should be 3-5 psi lower then the cut in pressure". What is the cut in pressure?

I had thought that this issue was due to dirt clogging something in the jet pump.

Joe
 
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Old 05-09-11, 08:29 AM
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You have a 40/60 switch. You said the cut in is 40. That is where the pump turns on.

Turn off power to the pump.
Open a faucet to let all the pressure out to zero.
Get a tire gauge and check the pressure in the tank at the schrader valve.
Set to 35 psi. Thats 5 psi less then your cut in psi of 40.
Turn on power and try it.

If you have too much air the at 40 psi the bladder will block the opening for a moment and you will have no, or low water. This is only for a moment until the pump re-establishes pressure.

So after 40psi you will see the gauge go to 0 for a moment then pump back up?

Did you mess with the air?

Mike NJ
 
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Old 05-09-11, 08:33 AM
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OK, I'll give that a try. I also read the same advice on the FAQ at Pumps Tanks Motors And Wells - Frequently Asked Questions
Do you know of any links to pictures and instructions on setting the PSI on the tank?
 

Last edited by waterwelldude; 05-10-11 at 07:36 PM. Reason: remove link
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Old 05-09-11, 09:02 AM
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Its all there in the link you posted.

Q. How do I set my bladder tank air pressure?


A. A bladder tank comes from the factory with pressure in the top of the tank. This air pressure will just about never be what the label says its supposed to be. So adjustments are necessary.
Pressure switchs that tell your pump motor when to start and stop are normally factory set at either 20PSI on and 40PSI off or 30 - 50, 40 - 60. I personally like 40 - 70. That gives a little more water between pump cycles. Regardless of the high pressure setting, the on pressure setting is the one that matters to the bladder tank. If your tank has 30lbs. in it and you want your pump to turn on at 30lbs. You will need to let out two pounds making the bladder tank air pressure 28PSI. The same with 20 on or 40 on. Make the tank pressure two pounds less than the on setting of the pressure switch.The reason for this is to have the pump turn on just before the tank reaches its air pressure setting. This prevents the tank from going completely empty when the air bladder hits the bottom of the tank. If this were to happen, the pressure in your plumbing would immediately go to zero since there is no more water to be pushed out of the tank. This condition is not desired when your in the shower. Of coarse the pump will kick on at this point making the zero condition only momentary, but nevertheless aggrivating.



Q. How do I check my Bladder Tank to see if it's gone bad?

Most Bladder Tanks made today have a rubber bladder that is filled with water from the Well Pump. It can eventually rupture over time or from improper air pressure settings. Others have a Bladder that holds the air and the water is put in the tank around the Bladder collapsing it. In either case, when the Bladder ruptures, water from the well will start to steal a little bit of air from the tank with every pump cycle. Eventually the tank will be full of water. If you push the tank from the top slightly sideways to gauge the weight of the tank, you should be able to see if it feels full or nearly empty (which is how it should feel if it's still working properly).

Another way to check your tank is to push the little stem in the schrader valve which is usually on the top or near the top of the tank. It will look just like the vavle on your car's tire. By pushing the stem in, you should be letting a little air out. If water comes out instead of air, your tank is definately bad.

If neither of the above methods work for you, turn off your pump and open a faucet somewhere to let all the water pressure out of your plumbing system. Take a tire gauge and check the air pressure in the tank. It should be two pounds less than the turn on pressure of your pump. If it is not at this pressure but you do have some pressure left, chances are the Bladder is still good and you can add the proper amount of air and keep using the tank. If you have no pressure left, there is a good chance the Bladder has failed.

Mike NJ
 
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Old 05-10-11, 03:32 AM
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thanks, that did the trick. The only thing is that the range of pressure changed. It used to be that the pump would come on at 40 and stop at 60 lbs. Now it comes on at 35 and stops at 73 lbs.

I want to bring that top number down a bit. There are two bolts and nuts inside the little box attached to the pump. They both have a spring on them and one is wider and longer than the other. Do you know which of those contols the upper range?

Joe
 
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Old 05-10-11, 06:48 AM
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Changing the pressure in the tank should not have changed the way the pressure switch reacts.

Look in the lid of the pressure switch. The big nut adjusts the cut in/off together. The smaller nut just the cut off.

High voltage in there so be very careful. Adjust with power off. The contacts are close to the nuts and it takes a second to slip and be electrocuted...... I have done it in my stupidity, and its not worth dying over.

Mike NJ
 
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Old 12-01-13, 01:28 PM
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Cut In/Out directions

I read the entire post, very helpful. Just want to understand which way to screw the cut in/out posts. Do I go clockwise to increase or decrease the cut in setting?

Thanks!
 
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Old 12-01-13, 02:15 PM
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El KECKO ............CW to raise/increase and CCW to lower/decrease..

This is old thread and am closing. Please start new thread...
 
 

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