I have a neighbor with an Edwards Aquifer well.  He had the pump replaced in August.  It started surging in January or February.  If they let it surge and then cycle the power using the pressure switch it will run smooth and pump water for hours and hours out of three hoses.  The guy that replaced the pump is saying that the well is low on water or collapsing and needs to be jetted which will cost $4,000.  Capacitors are good.  Pressure switch does not cycle when pump is surging.  Valve is wide open.  

The control box was replaced yesterday and it still surges.

If if surges and then runs fine after cycling the power wouldn't it be a pump or electrical issue and not a well issue?

Not an expert, but it sounds like an airlock issue maybe?  When they cycle it, the air burps out and it runs fine.  Pump stops and airlock is created rinse repeat surging?

  Hot tub pumps will do that sometimes.

How would it be sucking air if it pumps for hours without gurgling after cycling power?

Don't know, just thinking out of the box and have seen it happen to hot tub pumps.            Only a few things cause surging, air, or a lack of water and or both not much else that I can think of.   You would think once the pump is purged and running fine it should not surge again, but it sounds like it is?  So air is coming from somewhere or water is draining out of the pump creating a air lock and it starts surging again?

                                                                             

Back flow preventer is bad

Meaning the check valve?  I installed my own "deep well" pump in a 44' well and it has it's own check valve but called for another one.  I installed one ~ 38' up from the pump.  

They have a check valve right before the pressure tank.  The valve that they run wide open to witness it gurgling is before the check valve.  I wouldn't expect any water to go toward the tank if there is a gaping hole upstream of the check valve.  I am having them test the check valve by filling the pressure tank, turning the pump off, and opening the valve up.  I'll report back.

Are we talking about a surface centrifugal pump, a surface jet pump, or a submersible pump?

Also - do you have any idea of the static water depth, intake depth, and pumping water depth?

Submersible.  Idk what the water levels are, but the aquifer is almost exactly at the average and they've not had issues with the well going dry in the past.   Attached File

Check valve works.