Air lock

[Perryjay]

I have a shallow water well with the well being about 50 feet from the new jet pump. A check valve is 45 feet from the pump. I was unable to prime the supply line. It only took about 4 quarts of water to "fill" the line. I opened the line near the check valve and ran a camera up to the vertical bend in the pipe. It is a bit difficult to interpret the video but near the end of the line I saw what at first looked like dust floating in the in picture. A closer look made me think small bubbles. I recovered the camera and inserted a pressure sewer clean out and cleared the line. I closed up the line near the check valve and when I tried to prime the line from near the pump only a small amount of water would go into the pipe and the pump would not run for long before it was dry.

How doe that air lock get created? How do I break that air lock to prime the line and keep it from reoccurring?

I am open to putting a T near the check valve and priming from the bottom up if necessary.

Thanks for the help!

 

[Bannerman]

You didn't state the vertical distance between the water in the well and the inlet to the pump.

A shallow well jet pump can only lift water vertically about 24' while located at sea level, so with the elevation in Virginia between -10 and 6,253 ft, depending on the specific elevation where you live, the vertical lift distance maybe considerably less. To lift water a greater distance will require a deep well or convertible jet pump equipped with 2 lines, with the jet located within the well a short distance above the water line.

A check valve is 45 feet from the pump. I was unable to prime the supply line. It only took about 4 quarts of water to "fill" the line.

A jet pump will typically utilize a foot valve within the well. As a foot valve incorporates a check valve where the inlet screen is located, the foot valve should normally be the only check valve within the system. Utilizing a foot valve as the only check valve, there should be no issues priming the entire suction line.

If submersible pump was utilized instead of a jet pump, the check valve will be incorporated within the pump, and no priming would be required.

 

[Sponsor]

 

[Perryjay]

For detail:

According to the US topographic map I am at 33" above sea level.
From the well cap to the bottom of the well is 67'2".
From the well cap to the bottom of the pipe is 8'7" with no well foot.
From the well cap to the water level is 7'8".
From the cap to the check valve is 5'7".
From the check valve to the pump is 47'.
From the well cap to the pump there is 32" of rise.
The pump is a 3/4 hp jet pump.

My biggest question is how does this water/air lock get created while I am priming the 47' of pipe and how do I prevent it form happening again?

Thanks' for the help!

Yes I am living over a monster sink hole!

 

[Valveman]

A picture would help.

 

[Perryjay]

A picture of what part?

 

[Valveman]

The pump system that is "air locked".

 

[Perryjay]

I cut the line again near the check valve and the water ran out. I am installing a "T" fitting to allow me to fill the line from the check valve up to the house in an effort to push the air out at the pump and capping both ends.

 

[Bannerman]

I cut the line again near the check valve and the water ran out. I am installing a "T" fitting to allow me to fill the line from the check valve up to the house in an effort to push the air out at the pump and capping both ends.

You latest photo shows the pump's suction line with a 'T' with an open branch connection, directly preceding a Union fitting. No check valve is shown.

A Union in the suction line is a common location of air leakage, so it and the 'T' should be removed. To provide a means to prime the pump and piping, will be to install a 'T' with a removable plug directly above the pump's discharge fitting. Suction line typically = negative pressure while the pump is running, so even a tiny leak, will allow air to enter.

Since your pump's discharge connection is at a lower elevation than the through the wall section of suction line, it will be virtually impossible to prime the suction line unless the discharge line priming fitting is located substantially higher than the suction line. Suggest simply elevating the pump so the suction line will be below the pump's inlet, such as by placing the pump on a shelf or stand.

Even with elevating the pump and priming through the discharge line, the suction line will not be primed before any top side check valve (photo?). Since you said a check valve is located 5'7" from the well cap, and with the well's static water level being 7'8" below the well cap, then those sections (total 13'3") of suction line will likely remain filled with air.

To allow the entire length of suction line to become filled while priming, recommend removing any topside check valves, to utilize an in-well foot valve as the only check valve in the system.

 

[Valveman]

I guess that really could be called "air locking". As was said, priming should be done on the discharge side, not the suction side of the pump. Also, the suction should go up to the pump, not down. Air will accumulate in high spots in a suction line and cause a loss of prime, so the pump should be the high spot in the suction line.

 

[Perryjay]

I can comprehend the reply's of Valveman and Bannerman and will take the into the work.

Near the check valve I installed a T with a short section of pipe and fittings to allow me to prime the line from the bottom up. This pipe topped out taller than the height of the entire project. I took the cap off the T near the pump and filled the line from the bottom to overflowing at the pump. While overflowing I capped the the T at the pump. I filled the tall pipe to overflowing and capped it. I opened the well plug and filled that line to over flowing and plugged it while below the water level in the hole.

With fingers crossed I engaged the pump and within a few moments I had cool clear water running! I cut off the pump and raised the discharge line above the work and waited a few minutes and re-engaged the pump and it worked again with no problem. I'll check it again in the morning and see how it goes.

If I run into this problem again I will re-pipe at the pump to raise the pump higher that the rest of the project.

I thank you all for the insight to remedy my problem!

 

[Valveman]

Air from the water will accumulate in the high spot until it gets gulped into the pump, which will lose prime. Air is always coming out of the water. But glad you have water.