Arrived for furnace check on two systems. Started on upstairs system and static pressure is ok. Heat exchanger is good. Carbon monoxide test was 0ppm. All electrical is in range. I changed filter and humidifier pad. Blower has some dust build up. The main floor system static pressure is ok. Heat exchanger has some hot spots forming. Carbon monoxide test was 0ppm. All electrical is in range. I changed filter and humidifier pad. Both humidifiers are working properly. Systems are running at departure. Thanks for choosing LBA. Happy holidays!