I currently own 15+ house I need some professional advice from boiler guru on my boiler problem. I am hearing a strange water drop noise coming from a smokestack or inside of boiler whenever it rains outside. I was thinking that water might be dripping through smokestack and|or maybe into the boiler's furnance. I've attached picture of my aging but working well boiler & smokestack. I've also attached dripping noise sound clip in the middle of page.
ps: Thank you in advance.