Upstairs unit. Changed filter. Clean drain. Checked all electronic components. Clean flame sensor. Checked all safety switches. Checked amps on draft induced motor and blower motor. Both test fine. Upstairs furnace running as it should. main level unit. Clean flame sensor. Change filter. Clean drain. Checked all electronica Components. Checked all safety switches. Checked amps on draft inducer motor and blower motor. Motor motor stairs fan. Furnace running as it should.