Installing boilers is a craft that, done well, takes much skill and often lots of time. True hydronic craftsmen pipe everything level and plumb, ensuring that the system piping will be in place long after they are dead and gone. A time saver that I use is a “circulator blank” (pictured). The blank is lighter than an actual circulator, provides the same gap needed to slip in a circulator, and allows soldering of pump flanges without removing the gaskets, only to reinsert them afterwards.