Performed clean and check on 2 Tempstar furnaces and 1 General Aire humidifier. Found condensate drain clogged on the basement unit. Unclogeed it and found where a piece of the condensate tubing on the trap had been leaking causing rust in the middle part of the furnace cabinet. In the attic I noticed the gas vavle not firing. Checked for 24 V had nothing. Tapped on the gas valve and now all operations of both furnaces are correct. I advised customer to keep an eye on the attic unit. Customer is signing up for club membership.