Imagine yourself as a service technician. You’ve just been dispatched to a no-heat call in the early morning hours of a cold winter day. You know nothing about the system that you’re about to meet.
You arrive and are escorted to the basement by the homeowner, who’s obviously very concerned about how quickly you can restore comfort to his family.As you step off the basement stairs you see a boiler, several circulators, zone valves, lots of piping and a lineup of assorted controllers. Maybe something similar to Figure 1.