What actually happens during an OFTEC service
The nozzle is the smallest and most-abused part on the boiler, a precision-machined atomiser that turns oil into a fine mist for combustion. It wears every hour it runs. Standard practice is to replace it every service and match it to the size, angle and spray pattern listed by the manufacturer for that boiler and burner combination. Electrodes are cleaned and re-gapped, the photocell is polished, the fuel pump filter is renewed and pump pressure is checked with a gauge. The combustion head is stripped, baffles pulled, heat exchanger vacuumed and internal seals inspected. Once rebuilt, the boiler is fired and an electronic flue gas analyser is used to record CO, CO2, oxygen, smoke number, flue temperature and net efficiency. Those readings, not a hunch, dictate any adjustments to air, pressure or nozzle sizing.
