Furnace repair for the downstairs system. Signed the customer up for a new Comfort Club Membership. Replaced both of the clogged filters. Found the downstairs system with a bad flame safety sensor and a weak blower starter. Replaced both parts and the system is heating normally at this time. The upstairs system flame safety sensor is getting worn and the blower starter is weak (6.7 mfd of 10 rated mfd). The owner wants to wait for the upstairs repairs. Performed a combustion test on both furnaces. Found the downstair combustion all within range. The upstairs combustion has high oxygen content(10.5). Can improve the furnace efficiency by getting it calibrated. Overall, both furnaces are heating normally.