I have a gravity fed wter system coming from a spring. I have water coming into the main line, but not coming into the house. I'm sure it has to be a vaper lock but not sure how to remedy the problem.
IF there is any "positive pressure" from the spring, it will NOT vapor lock. The water will push the air out ahead of it.
Licensed residential and commercial plumber
That would depend on how the line is run. If any of the line rises high enough, it may rely on siphoning to overcome the high spot.