Main level not heating - 8 year old Trane System System not heating due to a blocked/clogged drain in the 90% furnace. Both the port of the inducer motor and the hose/port off the collector box were clogged. This was causing the system to hold a vacuum on the pressure switch which prevents the system from heating. I cleaned both hoses/ports, and cleared the drain at the internal ptrap and the 3/4 pvc as well. System is now heating properly. Thank you for choosing T.E. Certified, have a great day!