During this visit preventative maintenance and heating checks were performed. The bearings, amp draws, flame sensor signals, temperatures, condensation drains and other heating functions were checked for each unit. New filters were installed in all of the units. During todays checks several condensation drains were discovered to be clogged. They were cleaned today. In addition to this several flame sensors were cleaned. The units all passed this inspection. A combustion analysis was performed on the units and the supply ducts were checked for the presence of carbon monoxide. There was no carbon monoxide present in the occupied space and in the supply ducts during todays checks. Thank you Diego and Jon