when I started plumbing I ended up bouncing around to several companies and learned new or different ways from each place I worked and each mechanic I worked with...
I think I was lucky to start out in new construction, a set of 40 condo units, I was able to see and watch a house built from the foundation up, it let me see ALL the mechanical systems go in and how they were layed out and installed, this let me actually see how they worked...
I think this helped down the line when renovations or repairs were needed and I can visualize the piping or how it should be...
heating systems and boilers where part of the new construction phase and I helped install and run heat..
and in time I did it on my own..
each company did boilers a little different and learning when and where certain ways of installation were needed..from hydronic to steam, baseboard, radiant,kick heaters....
there is alot to learn before you attempt it on your own...
if you dont get it where you work now, and I dont know your end game if you want your own business, but sometimes bouncing around from companies is the best way to learn different aspects of plumbing...but thats a personal call you have to make..
my best advice to you is to buy up all the books a Dan Holohan puts out, they are great and written with some humor but very down to earth and understandable to the common person...here is a link to his website, but buy the books, they cover all aspects of heating and all the old systems you come across..
https://www.google.com/url?sa=t&rct...om/about-us/&usg=AOvVaw1pWI380SFA2LoM9o_pMwsw