Preformed fall service on two 80% furnaces the one in the attic is 2016 Mdl cleaned flame sensor checked amps on motors the coil was clean ran system in high and low stages system has a surge protector installed flue pipe and ductwork strapped correctly system operating correctly at this time the second system is in the garage and it was installed in June cleaned flame sensor checked gas pressure this system is single stage blower amps and inducer amps where great system has a surge protector installed customer changes filters regularly ðŸ˜ðŸ˜ðŸ˜merry Christmas system operating correctly at this time. Changed all filters