Performed function check on a 13 year old American standard heat pump. Refrigerant charge is acceptable. All amp draws are in tolerance. Blower wheel is dirty and should be cleaned. Highly suggest adding a compressor saver to help with the efficiency and reliability of the system upon start up. Due to the age and reliability of the current system, a comfort advisor is scheduled to meet with the customer next Thursday the 10th after noon. A generator maintenance has been scheduled for Thursday the 10th in the afternoon as well. Generac 24kw.