Performed pm on oil boiler Brushed and vacuumed flue pipe and heat exchanger Replaced oil filter, nozzle, and strainer Checked all electrical connections and safeties Performed combustion and smoke tests 5.4%o2 0 ppm co 0 smoke Got customer authorization for the 2 hi-vents recommended for replacement at last visit. Drained pressure from the system. Removed 2 old hi-vents and installed 2 new hi-vents. Filled system up with water and purged air out of all zones. Started and tested all zones. Had hot water coming back at all returns. Boiler pressure when leaving was 21psi