The provided #55 orifices are standard for altitudes up to 2

Efficient Power Draw: low 6

Proper installation of this replacement flue box is essential for maintaining the structural integrity of the burner section and preventing carbon monoxide leakage into the surrounding environment

allowing for immediate performance upgrades without replacing the entire coupling assembly

Lennox 97W45 Limit Switch R-407C The provided #55 orifices areThe Lennox 97W45 Limit Switch is a critical safety component designed for precise thermal regulation within residential gas furnaces and air handlers. Engineered as a normally closed thermal switch, this L140 30F secondary limit monitors heat exchanger temperatures to prevent overheating and potential heat exchanger fatigue. With a fixed temperature setting of 140F and a 30F differential, this Lennox high limit sensor ensures a reliable cutout when