jet-pump on well - lost prime and experience backwards flow

[electricpete]

jet pump pumps from well to tank. Cycles on and off based on tank pressure.

One day, water pressure goes to zero. Pump is running but not generating pressure.

Attempted to prime jet pump. No luck.

Turned off the jet pump. Hooked up an alternate supply of pressurized water to the residence. Noted a flow noise at the jet pump (even though it's not running). Flow noise disappears when jet pump discharge valve is closed, reappears when discharge valve is opened. It appears that water is flowing backward through the jet pump to the well. But tank pressure is no higher than normal.

What is your diagnosis/suggestion?
Thx.

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[zdas04]

What is your normal power fluid for the jet pump? What pressure is it supplied at? What is the suction fluid and pressure?

You can flow backwards through a jet pump (and when you do, you generally hear a lot of flow noise), but it always goes away when you re-introduce power fluid.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

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[PUMPDESIGNER]

Check valve in the jet pump intake line is leaking.
Could say more if you tell us what kind of jet pump and how it is installed.

Type - Shallow Well, Deep Well 2 Pipe, or Deep Well Packer.

Install - Directly connected to well. I assume you are in a lift situation (not artesian).

PUMPDESIGNER

 

[profengmen]

I ditto the check valve.

If this pump was running normally and then quit one day. Then the check valve probably went.

Of course, the well may have dried up.

The pump could have worn out or is clogged with iron deposts.

The well screen could be clogged.

But, since you hear water running backwards back into the well, the check is the first thing to check...

 

[electricpete]

It is a Gould's jet pump.

We found it is the check valve, also called a foot valve, which was leaking by. This prevented the pump from keeping it's prime.

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