Performing two dual fuel heating checkouts, on a planned maintenance agreement for two Lennox systems. Replacing air filters. Replacing humidifier pad and testing operation. Checking coils for cleanliness. Checking refrigerant charges. Testing electrical components and defrost. Performing combustion analysis’s on furnaces. Checking temp rises. Inspecting burners, flames sensors, and igniters. Checking flue pipes. No issues found on todays checkout.