Commercial buildings use boilers in two main ways: to make domestic hot water for sinks, showers and kitchens, and to heat the building through hydronic loops to radiators, fan coils or air handlers. Many larger properties have both. The plumbing around the boiler matters as much as the boiler itself: circulator pumps, expansion tanks, relief valves, mixing valves, storage tanks and the gas supply.
Common failures are ignition and flame faults, failed circulator pumps, leaking heat exchangers, relief valves that keep discharging, and scale buildup that cuts efficiency and overheats the exchanger. Older atmospheric boilers are often near the end of their life and far less efficient than current condensing units.
When replacement makes sense, we size the new boiler to the building's actual demand instead of copying an old oversized unit, plan the venting and gas supply, and stage the changeover to keep downtime as short as possible.