I had someone come over my house and winterize the sprinklers. He explained to me what he did: He said he closed the main valve to the sprinkler system, hooked up a compressor and blew out all the water from sprinkler pipes. He also, opened up the air valve so air can go in but water can not. After that I noticed the water is leaking slowly from the air valve. I called the same guy again and he told me the water is leaking because the main valve to sprinkler system is bad and I need to replace the same.
Can someone please point out if water is leaking from the air valve while the main sprinkler valve is closed, does it need to be replaced. Please note that while the air valve was in the closed position and main sprinkler valve open, no water leaked. Also, while keeping the main sprinkler valve closed, if I close the air valve too, water starts coming out of something connected above the air valve.