Performed oil pm on oil furnace and oil water heater 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 Furnace 6.7%o2 2ppm co 0 smoke Water heater 7.1%o2 1ppm co 0 smoke While performing the maintenance we found the water heater is from 2008. Would recommend replacing the water heater in the future. The average life of an oil water heater is around 15 years