The cell phone buzzed and the excited caller said, “That new boiler you sold us is not working. Can you send someone over right away? We have no heat.” I agreed and drove to the building.
Once there, the building manager led me to the boiler room. The hydronic boiler, thought to be new, was 3-1/2 years old. Mounted on the front of the boiler was three similar-looking controls all set for the same temperature — 160° F. The manager shrugged when I asked who changed the control settings. After tracing the wiring and adjusting the controls for the proper temperature, I wrote with a marker the correct temperature under each control. I used to write the settings on the control covers but found people sometimes will switch the covers. Once set correctly, the boiler operated properly and the building had heat. Commercial boilers typically have two or three controls; operating, limit, and sometimes, a firing-rate control.