Technician arrived on site for a routine safety heating tuneup checking over all electrical components no limited to blower motors inducer motors. All safety devices limit switches did an extensive CO test to prevent any dangerous gases from being admitted into the home check temporize didn’t find any hazardous problems with his heater, had his heat exchanger replaced one year ago found a flame sensor and ductwork to be a little bit dirty recommend those preventative upgrades. System is working good at this time.