Most Fraser steam work we do is preventive, because these 1960s ranches off Utica Road and 15 Mile have boilers that run well if someone looks after them. We like to see them in early fall, before the first cold week. A typical one is a Weil-McLain EG or a Burnham, one pipe steam, original or first replacement, coming up on 60 years.
First thing we do is a combustion test through the flue before the diverter. We read O2, CO2 and CO, then check draft. On an atmospheric boiler we look for O2 in roughly the 4 to 9 percent range and CO well under 50 ppm. If the numbers are off, we clean the burners and check the gas pressure before blaming the boiler.
Then the water side. Fraser boilers that have not been flushed build scale on the iron. You hear it as kettling, a rumble or crackle while it fires. We drain from the bottom until it runs clear, flush the wet return, and skim if the sight glass shows oil. Clean water boils sooner and burns less gas.
Last, the controls: pressuretrol and pigtail, low water cutoff blowdown, main vent check at the end of the header, and a look at every radiator vent. We tape a printout and a short log to the boiler. Next fall, whoever opens that basement door can see exactly what was done and when.