One of the most misunderstood portions of the commercial heating system is the gas train. The gas train is a series of components that safely feed natural or propane gas into the burner.
I like working with the control techs in our industry. They have such a passion for their craft. If left alone, they will control or monitor everything that moves, slides, shakes or switches. However, I do rein them in a bit when controlling a hydronic heating system. Several hard limits and a couple danger zones should be heeded. Of course, these should be verified with the boiler manufacturer.