Performed preventative maintenance for a crown boiler model #c247-400, serial #519900080. Upon arrival the system was calling for heat so I took a combustion analysis test and received the following results, 02 is at 15.3 and the co levels are at 19ppm. The water press is at 15psi and the limit is set for 190°F. There are no signs of leaks in the copper pipes. I powered the system down and removed and cleaned the burners and burner box. I powered the system back up and called for heat. Observed the system start normally. I let the system run until it teach the desired temp. The system is operating properly at this time.