27 yr old Trane furnace. Unit is in very poor condition. Bottom of furnace is rusting out, blower wheel is dirty, return duct has a pile of trash dirt and hair in it. Issue that was keeping furnace from running at times was a dirty flame sensor. Cleaned sensor, reduced high gas pressure, and cleared drain line as part of maintenance check. Customer does not have carbon monoxide detector at the moment but they are getting one. Customer has requested an estimate to replace the furnace. Appointment scheduled today 9-11 am. Daughter is dropping off check to the office for visit today.