Completed 2 system furnace repair and preventative maintenance check. In the upstairs unit, I discovered that there are no water safeties in the attic to prevent flooding if the drain line backs up or freezes. The blower capacitor is weak but still within the 10% range of factory recommended range. The capacitor may need to be changed in the spring. Also discovered that the furnace was producing high levels of carbon monoxide and needs to be calibrated. The gas line is not up to code. The main level and downstairs unit have an intermittent issue with the blower coming on which is making the unit shut off on a high limit. The downstairs also has no water safeties in place. Added water safety to the pan in the attic. Calibrated the combustion on the upstairs furnace and brought the CO levels down from 56 to 9.