Arrived on site to perform diagnostic on 20 year old unit. Homeowner states that unit is not heating like before. She can still feel it heating, but not to the extent that it used to. Cycled system for heat. Upon inspecting unit up in the attic, found that home has 3 units. 2 Of those units are combined into one and are working together to heat the downstairs, which is where the home is having trouble with heat. Units are wired in together with a daisy chain going from thermostat to one unit and then wired into the other. When cycled for heat, only one of the units is turning on, which is causing the downstairs to only recieve half of the airflow that it usually would. After troubleshooting, found that unit that is on top has a bad indoor blower motor, which is causing unit to cohort cycle on heat but bottom unit is still heating. System design and set up is horrible. Unit should be one larger capacity system instead of two lower capacity units. Systems are old and inefficient. Went ov