Arrived on site to perform condenser fan motor installation and furnace maintenance. Motor was installed. Performed full maintenance on 2004 carrier heater. Found that temperature rise was extremely high indicating that heat exchanger is at risk of damage from high temps. Advised that heat exchanger is inspected and tested for any possible defects but at this time client is aware unit is from 2004 and will most likely be replacing in the near future but cannot at this moment so would like to leave it the way it is and decline safety inspection. Single secondary motor control is the coming week that supplies power to indoor blower motor. Flame sensor had carbon buildup and was cleaned off. Inspected control board and found multiple burn marks possibly due to power outages. Gas line did not have drip leg as well. Recommend search protection to prevent any further damage to control board. At this time client is aware of all possible failure points. Will be sending recommendations over in