DCM1 service 1 of 2 heat completed changed (1) 12x24x1 filter,tested operations, outdoor AC is not operating found capacitor is bad 45/5 MFD reading 0MFD, system will not operate in AC mode. In heat mode found unit has crack (compromised) heat exchanger on the face plate and has potential to leak carbon monoxide into home. Current carbon monoxide readings in home is 1PPM. . Blower wheel is dirty to the point which negatively affects airflow and efficiency, Unit is from 2001 and is beyond life expectancy due to age and conditions of furnace would recommend replacement. Called Charlie and left a voicemail, attached is Heat maintenance checklist.