Performed preventative maintenance for heat pump system. Customer replaces the air filter. Inspected all the electrical components. Confirmed proper high and low voltages. Tested the amp draw of the blower, compressor and fan motor. All are operating within the manufacturer specs. Found the Honeywell UV light not working. This is due to bulb being burned out. Replaced bulb since I had one available on the truck. Tested that the system would go into defrost. System had a temp rise of 55° system is operating properly at this time. Customer asked for senior discount as well.