This Lennox 17F21 is typically supplied as the box assembly

The direct-operated or servo-operated design (depending on specific pressure differential requirements) provides reliable opening and closing cycles even under high-pressure conditions

this PTC start relay ensures precise current switching and thermal protection during the critical startup phase

Check the spark gap (should be approximately 0

Direct OEM Replacement: Replaces cross-referenced parts 9004470205 and 190714-000 without wiring modifications

Siemens Building Technology GMA121.1P Actuator 30067439-890 This Lennox 17F21 is typicallyThe Siemens GMA121. 1P is a heavy duty OpenAir electronic damper actuator designed for the rigorous demands of commercial HVAC systems. Engineering for reliability, this 24V spring return actuator delivers 62 lb in torque (7 Nm), making it an ideal choice for managing return air, exhaust, and face and bypass dampers in both constant and variable air volume (VAV) installations. The 2 position control (on off) logic ensures decisive operation, while the