Water Well and Pump Repair/well pump
QUESTION: I have a 50 ft residential well with a 1/2 hp myers pump that sand ate a hole in the casting behind the impeller. Apparently there is a trick to welding cast iron since two attemps left it still leaking minimally until finally it rusted shut or minerals stopped the leak for the moment. What is the trick to welding this--will brazing be more appropriate? Since this leak has stopped I have noticed the pump running twice when I just happened to be outside and after checking the house for leaks and finding none I suspect the checkvalve in the well is the culprit. Am I correct in assuming it is a brass valve in the bottom of the well? How would I fix that if that's the location? Seems to me if that is the case it could be remedied by taking the pump off the well and putting a checkvalve between the pump and the wellhead.
ANSWER: I have only welded cast iron a few times. I have brazed with fluxed brass rod and have arc welded with a nickel rod used strictly for cast. I have never heard of sand eating a hole in a pump though. Generally the impeller would be gone long before sand could eat cast iron.
One trick to welding cast is to preheat it first, then weld. Never try to cool it down, just let it cool at it's own pace.
The check valve in the well is called a foot valve. They can go bad, but rarely. If it is bad, you can install a check valve at the pump, but if you have a leak anywhere that can let air into the suction pipe, the next time the pump turns on, it will get a big shot of air and lose it's prime. Changing the foot valve is the wise thing to do. If you can see the well, take a picture or two and let me look at what you have.
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QUESTION: Thanks, Ok the pump is 28 yrs old and has been fine until now except for replacing pressure switch and motor once. The section behind the impeller must have been cut out by the sand that was in the well in the beginning for the first year or so. Can't imagine why it would be grooved the way it is otherwise though I see what you are saying inasmuch as the impeller is plastic one would think it would be eaten first. Don't know what part of the well I could take a picture of that would help you answer the question. I suppose there could be a leak under the slab or in the pvc around the outside of the house service the hose bibs there that is not apparent. I did check inside and none of the toilets sinks, water softener, water heater, washing machine appear to be leaking so I suspect the "footvalve". The pump is working fine, no air, no loss of prime, just that it seems to come on when there is no water running.Only noticed it twice in the last couple of weeks but that is curious that i would notice it twice when I just happened to be outside to hear it.How would I get the foot valve out of the well at this point since that is the proper way to do it--is it at the bottom of the well as I suspect?
The footvalve in the well should only be down 30'. That is of course if your system is a shallow well and not a deep well system. A deep well system has two pipes going to the well, shallow has only one. The shallow well system isn't too hard to work on. The deep well isn't for sissies, it's for die hard DIY'ers. And most of them lose the battle.
The reason I wanted pictures was so I would be able to tell you what you were up against. Some wells have pitless adaptors on them and they stick up above ground about a foot. Some are buried below the frost line. Some are in basements and were hand driven; these have no footvalve. Take a look around your yard for a pipe about 2" to 5" in diameter. If you find one, take a photo and post it here or on my Website. http://www.pumpsandtanks.com