The hermetic design features a displacement of 7

Dust-Resistant Design: The enclosed housing helps prevent debris and insects from obstructing contactor movement and causing high resistance at the connection points

As a veteran-verified part

though this fixed model is preferred for many OEM replacements to prevent field tampering

Do not use with capacitor-start motors

Carrier 330687-702 Burner Assembly 321702-401 The hermetic design features aWhen you're dealing with ignition failures or erratic flame signals in a residential furnace, replacing the Carrier 330687 702 Burner Assembly is the definitive fix for restoring combustion stability. This genuine OEM furnace burner replacement features a robust 3 inshot burner configuration integrated with a factory welded burner mounting bracket to ensure precise alignment with the heat exchanger inlets. Engineered for high efficiency gas furnaces,