Checked all operations in the heating and cooling mode and inspected furnace filter. Furnace filter was dirty and replaced with a customer supplied filter. Checked all electrical components and completed a combustion analysis of the unit. The oxygen levels were good and the flue temperature was good as well. The carbon monoxide being produced was near the upper limit meaning the should be monitored going forward. Checked all electrical and refrigerant components at the outdoor unit. Outdoor unit was very clean and looking good at this time. System is operating properly at this time. View visual findings from this job here - https://visionshare.xoi.io/?id=XA-19DB-47B32977D75243428804C61E8F594D1E