Sign 2 Comfort club memberships. Complete 2 system furnace repair and preventative maintenance check. Change both filter, check safety and operations. Find main level system 2-year-old, find system operating within manufacturer spec. No concern at this time. Repair damage filter door. Find upstairs system 26 year years old operating with damage control board and burnt resistor, worn flame sensor and worn ignition. System blower assembly dirty and motor worn. Find gas line not up to code and system operating but under-fire and high co level. System also missing in-line water protection for system in attic. Due to system age and poor conditions, suggest to upgrade system and not repair. System operating at this time.