DCM1: Heat complete, checked filter (1)16x25x4, system is fully functional and operating within manufacturer specifications at this time, Heat maintenance checklist below.
Upon arrival Heat struggling to keep up, at 75 degrees upon arrival, unit was going out on high limit, filter (1) was not changed since 2022 filter B was not changed since 2020, replaced (2) 20x20x1 filter, increased blower speed in heating mode, system is operating properly at this time.