Well pump loses prime occasionally

[DJT]

I have a well that has a water level at 18' , piping goes down 60'.
We have never lost water or had the level drop below 18'.

1 hp jet pump.

My problem is that the pump will occasionally lose its prime. I have a priming switch on the side of the regulator so it comes back on quickly.

Is this a problem with the foot valve?
Is my piping too close to the bottom and occasionally getting debris in the foot valve.

 

[WorthFlorida]

It could be. It may be hanging up by a small stone or just worn out. Is there a check valve between the pump and pressure tank? When you lose prime can water still be drawn from the pressure tank until the pressure drops too low? If you can still draw water then the check valve is good.

 

[Sponsor]

 

[Reach4]

Two inch casing?

Is your priming switch a lever on the side of the pressure switch?
Two pipes connect between the pump and the well, or one?

The problem is probably not the foot valve, because the pump should have kicked on in the face of a small leak. You may need to drop the air precharge on the pressure tank, or you may have a blockage between the pressure switch and the pressure tank. Clean the nipple.

If 3 or more inch casing, consider a submersible pump.

 

[DJT]

4" casing
Yes, priming switch is a lever on the side of the pressure switch.
Prior pump had 2 pipes, had everything replaced, now it's just a single pipe. (Replaced everything because of this problem)

It will work just fine for a week or a month (sometimes more) then just lose prime

 

[Reach4]

4" casing
Yes, priming switch is a lever on the side of the pressure switch.
Prior pump had 2 pipes, had everything replaced, now it's just a single pipe. (Replaced everything because of this problem)

It will work just fine for a week or a month (sometimes more) then just lose prime

The only check valve should be the foot valve. I would set the air precharge to 5 psi below the cut-in pressure for the pump. It takes some time for the jet pump to get going.

If you have a 4 inch pvc casing, you could use a "4 inch" submersible pump. If you have a 4 inch steel casing, a "3 inch" Grundfos SQ pump would be a better choice. The submersible pumps are quieter, and do not need priming. They also use less electrical power, but that is a small consideration.

 

[DJT]

Thank you for your help, it is much appreciated

 

[LLigetfa]

To confirm/correct the terminology, losing prime generally means that air found its way into the pump and it usually involves manually adding water to prime the pump. It does not sound like that is what you are experiencing.

It sounds like you are losing pressure below the low pressure cut-off threshold which is somewhere around 10 PSI below the pump cut-in setting. A common cause for this is the air precharge on the tank is set too high causing the pressure to drop when the tank empties before the pump can supply enough volume to keep the pressure up. For that reason, it is generally advised to set the precharge 5 PSI below the cut-in.

There can be other reasons for a delayed pump start, such as a clogged tube or riser pipe on the pressure switch, or crud trapped in the pressure switch. Another common mistake is where the air pressure gauge is not reading the same as the water pressure gauge resulting in not having 5 PSI less air pressure below the cut-in.

 

[Bannerman]

Prior pump had 2 pipes, had everything replaced, now it's just a single pipe.

How are you sure the water level does not exceed 18'?

At sea level, water can only be drawn 25' vertically. Montana is approx 1000' above sea level so the maximum vertical draw distance will be reduced approx 2' to 23'.

The prior 2-pipe jet pump setup would allow greater than 23' vertical lift only if the adaptor was physically located down inside the well so the single pipe section below the adaptor but above the water level was less than 23'. Now with a single pipe setup, the 23' vertical limit will apply. Perhaps the well's static level is 18' when there hasn't been any water drawn for several hours, but recovery maybe slower than it had been previously so the static level may be lower once a volume of water has been drawn from the well.

 

[Valveman]

What Bannerman said!