HVAC Maintenance- 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 8.2%o2 5ppm co 0 smoke While performing the maintenance we found the there is debris in the chimney that is close to level with the flue pipe entrance. Recommend having the chimney cleaned before the debris fully blocks the flue pipe entrance.