Performed two system heating maintenance Attic system: 2023 Lennox dual fuel system Two stage 96% efficient LP-fired furnace 3 ton heat pump 16x25x1 filter is good Left a new one with the furnace Corrected drain safety switch wiring to shut the furnace and AC down in the event ofman drain backup Run tested heat pump Getting 110⁰ Vapor line temperature and 17⁰ temperature rise Pulled and cleaned furnace flame sensor Cleared condensate ports internal to the furnace Run tested furnace High fire Manifold pressure set to 10"wc with reference to the sealed burner box Temperature rise 40⁰ Low fire pressure set to 4.5" Temperature rise 30⁰ Main system: 2023 Lennox dual fuel system 18 SEER inverter heat pump 2 stage 96% propane furnace Ductwork massively undersized 5 ton heat pump requires 2000CFM of air Return drop is 10x24" with one side utilizing a 16x25x1 filter Return trunk is 8x24 Ductwork needs to be at least 30x12 with a 20x25x4 filter, preferably a 24x25x4 Discussed issue of airflo
