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Marc, Plumber
Category: Plumbing
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Experience:  Plumbing heating & home maintenance contractor
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Shallow well jet pump stays at 25 psi and will not build up

Customer Question

shallow well jet pump stays at 25 psi and will not build up pressure
Submitted: 2 years ago.
Category: Plumbing
Expert:  Rick replied 2 years ago.
Is this a new install? what type of well? dug? driven point?
Customer: replied 2 years ago.

new install - sand point with check valve out of the floor to the pump to the tank. Before it was 1-2 psi barely water coming out. Put in new sand point and check valve - reached 25 psi - good flow out of fixtures - not reaching cut - out level. When I manually shut off pump the pressure goes to 0 psi - when I turn it on it quickly goes to 25psi. It has a valve after the tank when I close the valve it doesn't build pressure - it stays at 25psi.

Expert:  Rick replied 2 years ago.
How deep is the water in the suction line?
Expert:  Rick replied 2 years ago.
How high does the pump have to lift the water out of the ground?
Customer: replied 2 years ago.

water table is 12'. Total is around 22". If I have a check valve why would the pressure drop?

Expert:  Rick replied 2 years ago.
Because you're only generating pressure while the impeller is turning. I'm not real familiar with driven point problems. I'm going to open this back up to my colleagues. Maybe one of them has an idea. If I can think of a likely culprit I'll be back. Please don't respond (even to acknowledge this post) until one of us gets back to you. responding first will only delay your answer.
Expert:  Phil replied 2 years ago.
Welcome! .

You should not loose tank pressure with a check valve between the tank and the pump discharge...

With a check valve in the pump suction, depending on size and type of check valve you can restrict the pump suction and limit its head pressure output potential....

If the check valve is not a soft seat variety it can leak as well, that is unusual with new installations... a sand point however could easily leave a tiny spec of sand in check valve seat that would cause the problem.

Tell me if the tank is a bladder tank or not, and what the air pressure on the bladder reads when the pump is running and when the pump is not running.

We can go from there.
Customer: replied 2 years ago.

No check between the outlet pump and the tank. Only on suction side. Bladder 20 gallon tank. Around 28 psi when running same when off manually.

Expert:  Phil replied 2 years ago.

Hello again,

Look this article over for background information, The try reducing the air pressure in your bladder tank to 25 psig and tell me how that goes.

There are many possibilities, this is step number 1.