Why is the ductwork dripping?

My boiler is as solid as a tank and can never die.  Most people don’t realize that a boiler can last up to 50 or 80 years with the right servicing.  At this point, my boiler is probably in it’s late 40s or 50s and usually only ever needs a replacement part here or there, otherwise it is always good to go.  It heats this whole place without once breaking a sweat. I can also heat my plumbing by being attached to my water heater and it can also heat my pool by being attached to it.  I don’t dare do any of this though because I can’t fathom breaking it and have to get a different heating system. I was living the high life because I knew a perfect HVAC technician that knew the ins and outs of my boiler system.  Twice a year he would come by and oil and tighten any loose components and make necessary repairs and it was good to go. But he just retired and I can’t find anyone who can replace him. Not only that, but my boiler is also extremely old and none of the newer techs have ever seen one.  It’s not made anymore and neither are the replacement parts; boiler maintenance must be a dying artform. A tiny number of heating and cooling specialists know anything about handling a boiler, and if they have before, they don’t resemble my model. I can’t risk letting my boiler go a whole year without a service and maintenance call.  I need someone who understands this equipment; perhaps an old timer in their 80s who’s still working. though.

HVAC equipment