Performed preventative maintenance for boiler system. Cleaned out burners and burner pan. Inspected the water and gas piping for leaks. Found no leaks at this time. Inspected all electrical components within the boiler. All are working as they should. Confirmed proper high and low voltages.The flue damper automatically opens and closes without issue. Performed a combustion test on the system. Boiler is operating at 83% efficiency with a CO level of 22ppm. Expansion tank is holding rated pressure with no breaks in the diaphragm. Water pressure on arrival was still at 18psi. Found no abnormal cold spots in baseboard. This confirmsAuto fill is maintaining proper water pressure all the time. System is operating properly at this time.