Client called to have furnace serviced. Tech went out, Tech tested the heating system: checked gas pressure, temperature, exhaust fan amperage test, blower motor amperage test, flame rectification sensor test, exhaust fan vacuum test, ignition system tests, pull and inspected both blower motor assembly and their capacitors. Inspected both heat exchangers for any deficiencies. Tech found the ducts are getting dirty, the ignition system is starting to wear out, tevh also found the exhaust system was starting to fail.